It is thought a garden to be a perfect setting for the house.

• Correct sentence: It is thought that a garden would be a perfect setting for the house.

Unless you try to work hard, you will fail in the exam.

• This sentence is already correct.

Unless you don’t try to work hard, you won’t fail in the exam.

• Correct sentence: Unless you try to work hard, you will fail in the exam.

life/ city/ peaceful/ as/ life/ the countryside.

• Correct sentence: Life in the city is not as peaceful as life in the countryside.

I wish you give me a chance to tell you the truth.

• Correct sentence: I wish you would give me a chance to tell you the truth.

I was annoyed that my brother hadn't clean the house before he went out.

• Correct sentence: I was annoyed that my brother hadn't cleaned the house before he went out.

The man you met at the party last night is a famous actor.

• This sentence is already correct.

The man that you met at the party last night is a famous actor.

• Correct sentence: The man whom you met at the party last night is a famous actor. (Or The man you met at the party last night is a famous actor.)

The man whose you met at the party last night to be a famous actor.

• Correct sentence: The man whom you met at the party last night is a famous actor.

The man who you met at the party last night a famous actor.

• Correct sentence: The man who you met at the party last night is a famous actor.