•Rack one's brain(s) (idiom) -

To think very hard in order to try to remember something, to solve a problem, etc.（绞尽脑汁，搜肠刮肚）

Examples:　　

1.I've been racking my brain, but I can't remember his name.

2.He racked his brains all weekend trying to think of a solution to the problem but in vain

•Absolve (sb) from (sth) (phrasal verb) -

To declare that someone is free from guilt blame or responsibility for something.（解罪，开脱）

Examples:　　

1.The evidence that the defense attorney presented in court convinced the jury to absolve his client from the crime.　　

2.The report absolved her from all blame for the accident.

•Interfere with sth (phrasal verb) -

To prevent something from happening or developing in the correct way.（妨碍，干扰）

Examples:　　

1.Mum says I can get a part-time job if it doesn't interfere with my homework.　　

2.Even a low level of noise interferes with my concentration.

•Pin one's hopes on sb/sth (idiom) -

Put one's hope or trust in someone or something.（寄希望于……）

Examples:　　

1. Why are you pinning all your hopes on him when you know he is going to let you down?　　

2.She'd pinned her hopes on an early acceptance to the college but it didn't materialize.

•Have faith in (sb/sth) (idiom) -

To have confidence in someone or something.（对……有信心，相信）

Examples:　　

1.I know you'll pass this test – I have faith in you. We had faith in her ability to succeed.