Time clauses

· With time clauses we use the present simple or present perfect, but NOT future forms. We use words and expressions such as while, before, after, until / till, as, when, whenever, once, as soon as, as long as, by the time, etc to introduce time clauses.

- By the time he arrives, it will be dark. (NOT; By tho time he will arrive...)

· We also use the present simple and present perfect but NOT future forms after words and expressions such as unless, if, suppose/supposing, in case, etc.

- If she wants more information, tell her to call me. (NOT-lf she will want..,)

· We use future forms with: when - when it is used as a question word.

- When will you be seeing Mike next?

· if/whether - after expressions which show uncertainty, ignorance, etc, such as I don't know, I doubt, I wonder, I'm not sure, etc.

- I doubt whether she will come tonight.

PAST TENSES

Past Simple Tense

We use the past simple:

· For an action that happened at a definite time (stated or implied) in the past. Tina arrived in Vienna last week.

· For actions that happened immediately after one another in the past. He left the house, walked to the station and caught the 5:05 train to New York.

· For past habits or states which are now finished, usually it is used with used to: I worked for Morton’s when I was younger. Now I don’t. I used to work for the company when I was younger.

Used to

We use used to + infinitive to refer to past habits or states.

· In such cases used to can be replaced by verb in the past simple with no change in meaning.

- When I was younger, I used to go to Wales on holiday every year. When I was younger, I went to Wales on holiday every year.

	The time expressions used with the past simple: yesterday, then, when?, last night /week /month /year; last Friday / October; three days/weeks ago; in 1999, how long ago?