______ children believe they can succeed, they will never become totally confident．
| A．If | B．Since | C．Once | D．Unless |
Einstein’s most famous theory is ______ we call the Theory of Relativity.
| A．what | B．that | C．which | D．why |
Not everyone has realized what ________important part the balance of ________nature plays in their life.
| A．an；the | B．/；the | C．an；/ | D．the；/ |
—— Go for a picnic this weekend , OK ?
—— __________. I love getting close to nature.
| A．I couldn’t agree more | B．I’m afraid not |
| C．I believe not | D．I don’t think so |
Don’t forget _____ the book to the library when you finish _____ it.
| A．to give back ; to read | B．to return ; reading |
| C．returning ; reading | D．returning ; to read |
Marry was so excited _____ she received an invitation from her friend to visit Beijing.
| A．where | B．that | C．why | D．when |