Correct the mistakes in these sentences. 1. We lived here since 1997. 2. I've been ill since two days. 3. How long do you know him? 4. Susie has seen a good film last night. 5. We've finished our homework just. 6. I've already wrote three letters.

We have lived here since 1997.
(The correct tense is present perfect, which is used to talk about actions that started in the past and continue to the present.)

I've been ill for two days.
(When referring to a period of time, we use "for," not "since." "Since" is used with specific points in time.)

How long have you known him?
(In this case, the present perfect tense is needed, so it should be "have known.")

Susie saw a good film last night.
(The simple past tense is used when referring to a specific event that happened in the past, like "last night.")

We've just finished our homework.
("Just" is placed before the main verb, and the present perfect tense is used to talk about recent actions.)

I've already written three letters.
(The past participle of "write" is "written," not "wrote.")