20160411 - have (got) to

	A	B	C
1	Have (got) to
2	Function	Explanation	Examples
3	An ‘external’ obligation (necessity) that comes from “outside”. Present.	MUST is possible but HAVE (GOT) TO is more commonGOT is often used to convey a sense of urgency.	I have to work from 9.00 a.m. till 5.00 p.m.Harry has (got) to go to Hong Kong at short notice for his firm.He has (got) to get up very early to catch his plane.
4	An obligation (necessity) that comes from “outside”. Future.	MUST is possible but WILL HAVE (GOT) TO is more common	I see you’ve got only three decent shirts; you must/’ll have to/’ll need to buy some more when you get there.
5	Past obligation (necessity)	MUST is NOT possible in the past but HAD TO is	I had to leave early because I wasn’t feeling well.I didn’t need to/have to go to the bank, because I got enough money from the office to take with me.
6	Absence of obligation (necessity) in negative sentences	DON’T HAVE TO, HAVE NOT GOT TO (stronger sense of ‘external’ obligation), DON’T NEED TO/NEEDN’T (weaker sense of ‘external’ obligation), NEEDN’T HAVE (stronger) is used to say that there is no obligationMUST is used to tell people not to do things	You needn’t / don’t have to /haven’t got to work tomorrow if you don’t want to.You mustn’t move any of the papers on my desk.
7		DIDN’T NEED TO/HAVE TO is used to express absence of obligation in the past when we did NOT do anything BECAUSE it was not necessary and NEEDN’T HAVE when we DID do something ALTHOUGHT it was not necessary.	I didn’t need/have to water the flowers, because it was going to rain and it did.I needn’t have watered the flowers, because it started to rain soon after anyway.
8		The differences between MUST and HAVE TO	You must go and see the boss. = I want you to go and see the boss.You’ve got to go and see the boss. = The boss wants you to go and see him.
9	Past tense in reported speech	MUST can be used after a past reporting verb as if it were a past tense	I decided that I must stop smoking.
10	Prohibition. Negative sentences.	MUST NOT means DON’T DO.DON’T HAVE TO means YOU CAN DO BUT IT’S NOT NECESSARY Instead of DON’T HAVE TO (HAVEN’T GOT TO) in British English NEEDN’T is often used.	You mustn’t tell George. (Don’t tell George.)You don’t have to tell George. (You can if you like but it isn’t necessary.)
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