The day breaks，______ the birds are singing.
| A．because | B．as | C．since | D．for |
________ I'm mistaken, I've seen that tall man at a party before.
| A．If | B．As |
| C．Unless | D．When |
Beijing is ranked first in terms of traffic jams and expenses for culture ________ Guangzhou is more open to peasant workers than Beijing and Shanghai.
| A．when | B．since |
| C．while | D．because |
________ he stops driving himself like this, he'll have a breakdown.
| A．Until | B．Once |
| C．Since | D．Unless |
________ my teacher didn't tell me directly, I still felt that I didn't live up to her expectation.
| A．When | B．Since |
| C．As | D．While |
I was wondering what to do with my car which won't start ________ a kind man offered to help.
| A．while | B．and |
| C．so | D．when |