Children’s brains cannot develop properly _________ they lack protein.
| A．because | B．since |
| C．when | D．unless |
The _____ of the trees in the water was very clear.
| A．mirror | B．sight | C．reflection | D．shadow |
Today, housework has been made much easier by electrical _____.
| A．facilities | B．appliances | C．instruments | D．equipment |
Pack the cake in a strong box, or it might get _____ in the post.
| A．splashed | B．spilt | C．crushed | D．crashed |
Professor Smith and Professor Brown will _____ in giving the class lectures.
| A．exchange | B．alter | C．shift | D．alternate |
Despite all the evidence to the contrary, the witness _____ that his story was true.
| A．stuck out | B．stood out | C．kept down | D．held up |