Three hundred firemen raced to the hotel after a smoke detector ______ the alarm soon after midnight.
| A．set off | B．set out | C．gave away | D．gave off |
Thailand has decided to begin building its first standard-gauge railways in cooperation with China, ______may cost $12.2 billion.
| A．when | B．that | C．it | D．which |
— Excuse me, can you show me the way to the nearest bus stop?
— Sorry. I’m a stranger here. I ______ here until my guide arrives.
| A．stand | B．have stood |
| C．am standing | D．will stand |
When Mary arrived she found all her children ______ for nearly two hours.
| A．have gone to sleep | B．fell asleep |
| C．was falling asleep | D．had been asleep |
The silence of the library ______only by the sound of pages being turned over.
| A．had been broken | B．breaks |
| C．broke | D．was broken |
President Xi has advised young people to avoid staying up late, ______ heated response from Internet users on microblog.
| A．having drawn | B．drawing |
| C．to draw | D．Drawn |