【推荐1】The secrets of space are still ________ (know) to most of us.

【推荐2】The letter “x” often represents a(n) ________ number in some Math exercises. (know)

【推荐1】I could not understand how someone with so many awards could be ________ (不出名的) to me.

【推荐1】The art lesson is really r_____ for me.

【推荐2】Mary wants to borrow my book because she thinks it is very ________ (use).

【推荐3】用括号内所给单词的适当形式填空, 每空格限填一词。
1. Helen eats a banana and two __________ (tomato) for dinner.
2. September is the ___________ (nine) month of a year
3. Our teacher says geography is very ____________ (use) for us.
4. The ruler isn't ____________ (she). It's John's
5. Sally __________ (real) likes fruit and vegetables She thinks they're healthy
6. There are two _____________ (dictionary) on the desk.
7. —Let's play basketball after class.
—That sounds ____________(relax)
8. —When is _____________ (woman) Day?
—It's on March 8th