Present Continuous
É um tempo verbal usado para indicar ações que estão em progresso no presente; no momento da fala.
Ele é empregado para falar sobre situações temporárias, ações contínuas que estão acontecendo.
Como as frases com Present Continuous referem situações que ocorrem no momento da fala, é comum observarmos a utilização de advérbios de tempo nas frases.
Alguns advérbios de tempo comumente utilizados são now (agora), at the moment (no momento) e at present (no presente; atualmente).

EXEMPLOS:
She is talking to her mom now. (Ela está falando com a mãe dela agora.);
Are they studying at the moment? (Eles estão estudando no momento?);
She is American, but she's living in Canada at present. (Ela é americana mas está morando no Canadá atualmente.)

FORMAÇÃO DO PRESENT CONTINUOUS
O Present Continuous é composto por um verbo principal e um verbo auxiliar.
Utiliza-se o verbo to be no Simple Present (am/ is/ are) como auxiliar e ao verbo principal, é acrescida a terminação –ing.
Ou seja, na construção frasal esse tempo verbal segue o seguinte padrão de formação:
Sujeito + verbo to be + verbo com -ing + complemento
She is watching TV. (Ela está assistindo TV.) ou She’s watching TV.

FORMA NEGATIVA
Na forma negativa, acrescenta-se o not depois do verbo to be, ou seja, a construção das frases negativas é feita da seguinte forma:
Sujeito + verbo to be + not + verbo com -ing + complemento
Exemplo:
She is not watching TV. (Ela não está assistindo TV.) ou She isn’t watching TV.

FORMA INTERROGATIVA
Na forma interrogativa, o verbo auxiliar to be aparece no início da frase. O padrão da estrutura das frases interrogativas é o seguinte:
Verbo to be + sujeito + verbo com -ing + complemento
Exemplo:
Is she watching TV? (Ela está assistindo TV?)

Exemplo: (She/ write/ on the board)
                She is writing on the board.
               
               (You / play / guittar)
               You are playing guittar.

                (Harry / listen to / music)
                Harry is listening to music.

Past Continuous
O Past Continuous (Passado Contínuo), também conhecido como Past Progressive (Passado Progressivo), é um tempo verbal utilizado para indicar ações contínuas que ocorreram no passado.
Confira os casos onde o Past Continuous deve ser utilizado.
1. Para expressar duas ou mais ações que acontecem ao mesmo tempo no passado
Nesse caso, é muito comum o uso da palavra while (enquanto).
Exemplos:
• I was reading a book while he was watching TV. (Eu estava lendo um livro enquanto ele estava assistindo TV).
• My father was washing the dishes while my mother was vacuumming the house. (Meu pai estava lavando a louça enquanto minha mãe estava passando o aspirador na casa.)
• While the girls were playing basketball, the boys were playing volleyball. (Enquanto as meninas estavam jogando basquete, os meninos estavam jogando vôlei.)
2. Para expressar uma ação contínua no passado, que já estava acontecendo, quando outra mais pontual ocorreu
Nesse caso, a ação pontual no passado é expressa pelo Simple Past (Passado Simples).
Exemplos:
• I was watching Brazil’s game when the phone rang. (Eu estava assistindo o jogo do Brasil quando o telefone tocou.)
• We were talking when the teacher arrived. (Estávamos conversando quando a professora chegou.)
• They were studying when somebody rang the bell. (Eles estavam estudando quando alguém tocou a campainha.)
3. Para expressar uma ação contínua habitual que ocorria no passado
Nesse caso, geralmente são empregados advérbios de frequência como os indicados na tabela abaixo.




Advérbios de frequência
constantly constantemente
often frequentemente
rarely raramente
occassionally ocasionalmente
weekly semanalmente
monthly mensalmente
yearly anualmente








Exemplos:
• He was constantly owing money to his friends. (Ele estava constantemente devendo dinheiro aos amigos.)
• She was often asking for help. (Ela estava sempre pedindo ajuda.)
• They were always making the same mistakes. (Eles estavam sempre cometendo os mesmos erros.)
4. Para estabelecer uma relação temporal entre uma ação contínua que ocorreu no passado e o momento presente
Nesse caso, é muito comum o uso de certas expressões de tempo.
Algumas das mais usadas são as indicadas na tabela abaixo.
Expressões de tempo
by this time por esta hora; por esta época
yesterday ontem
last night ontem à noite
last year ano passado
last month mês passado

Exemplos:
• By this time last month, we were celebrating his graduation. (Mês passado, por esta hora, estávamos comemorando a formatura dele.)
• She is wearing a skirt today, but she was wearing a dress yesterday. (Ela está usando uma saia hoje, mas ontem estava usando um vestido.)
• We were living in Miami last year. (Nós estávamos morando em Miami no ano passado).

Regras de formação do Past Continuous
O Past Continuous é formado pela união do verbo auxilar to be conjugado no Simple Past (Passado Simples) + gerúndio (-ing acrescido a um verbo principal).
As flexões do verbo to be no Simple Past são was e were.
Was é usado com a terceira pessoa do singular (he, she e it) e were é usado com as demais pessoas verbais (I, you, we e they).
Confira abaixo a conjugação completa do verbo to be no Simple Past.
Verbo To Be
Uma vez que o verbo to be é o auxiliar do Past Continuous, relembre sua conjugação no Simple Past:
Affirmative Negative Interrogative
I was I was not/ I wasn't Was I...?
You were You were not/ You weren't Were you...?
He was He was not/ He wasn't Was he...?
She was She was not/ She wasn't Was she...?
It was It was not/ It wasn't Was it...?
We were We were not/ We weren't Were we...?
You were You were not/ You weren't Were you...?
They were They were not/ They weren't Were they...?
 Forma Afirmativa (Affirmative Form)
Nas frases afirmativas no Past Continuous, a forma correta de construção frasal é:
Sujeito + Verbo to be no Simple Past + Verbo principal com –ing + Complemento
Exemplo: She was going to my house. (Ela estava indo para a minha casa.)

Forma Negativa (Negative Form)
Nas frases negativas, utiliza-se o not após o verbo to be. Observe a formação correta:
Sujeito + Verbo to be no Simple Past + not + Verbo principal com –ing + Complemento
Exemplo: She was not going to my house. (Ela não estava indo para a minha casa.)
Na forma negativa, o verbo to be pode ser usado na contracted form (forma contraída):
Full form Contracted form
I was not I wasn’t
You were not You weren’t
He/She/It was not He/She/It wasn’t
We were not We weren’t
You were not You weren’t
They were not They weren’t
 
Forma Interrogativa (Interrogative Form)
Na formação das frases interrogativas, a seguinte construção frasal é utilizada:
Verbo to be no Simple Past + Sujeito + Verbo principal com –ing + Complemento
Exemplo: Was she going to my house? (Ela estava indo para a minha casa?)

Exemplo de conjugação no Past Continuous
Verbo to go (ir)

Affirmative Negative Interrogative
I was going   I was not going/ I wasn't going Was I going...?
You were going You were not going/ You weren't going Were you going...?
He was going He was not going/ He wasn't going Was he going...?
She was going She was not going/ She wasn't going Was she going...?
It was going It was not going/ It wasn't going Was it going...?
We were going We were not going/ We weren't going Were we going...?
You were going You were not going/ You weren't going Were you going...?
They were going They were not going/ They weren't going Were they going...?