Tom owns _______larger collection of _______ books than any other student in our class.
| A．the; 不填 | B．a; 不填 | C．a; the | D．不填; the |
Jerry has promised to keep the secret, so he won't tell anyone __________ asked to.
| A．until | B．now that |
| C．unless | D．even though |
Playing on a frozen sports field sounds like a lot of fun. Isn't it rather risky，__________？
| A．though | B．also |
| C．either | D．too |
Hot __________ the night air was, we slept deeply because we were so tired after the long journey.
| A．although | B．as |
| C．while | D．however |
__________ the police thought he was the most likely one, since they had no exact proof about it, they could not arrest him.
| A．Although | B．As long as |
| C．If only | D．As soon as |
__________ H7N9 is a deadly virus, it is still safe to eat thoroughly-cooked chicken.
| A．Until | B．While |
| C．If | D．Since |