While she is a lovely girl, she be extremely difficult to work with.
| A．may | B．must | C．should | D．can |
Vitamin D gets produced when animals are exposed to direct sunlight, for＿reason, it
is always advisable to give them chances to spend time in the sun.
| A．whose | B．that |
| C．which | D．its |
In the middle of February, the weather＿＿favorable for work, the workers began to repair and secure the dam of the river.
| A．was | B．being |
| C．would be | D．to be |
The local guide told the explorers that ropes and knives were＿＿wanted to go into the inner part of the mountain must take along.
| A．that whoever | B．what who |
| C．what whoever | D．that who |
In many cities of China, if an ambulance is＿＿in a traffic jam, police will respond to the emergency.
| A．held up | B．held back |
| C．held down | D．held out |
一I think I saw Mr. Smith at yesterday's party.
一He＿＿there. He is now on a business trip in Greece. And he left the day before
yesterday.
| A．mustn't have been | B．couldn't have been |
| C．might not be | D．should not be |