The dog has a(n) _______ sense of smell while the rabbit has a sharp sense of hearing.
| A．acute | B．cautious |
| C．flexible | D．valid |
Each girl present at the party was wearing a flower in the hair, which _______ their beauty.
| A．added | B．added up | C．added to | D．added up to |
He decided to _________ the club for old men and play chess there.
| A．take part in | B．join in | C．attend | D．join |
According a recent report, there are _________ to be 1.35 billion people in China in 2017.
| A．decided | B．determined | C．reported | D．estimated |
In the old days, some wealthy people killed animals just for the ______ of it.
| A．joy | B．pleasure | C．fun | D．play |
Xiao Li was about to cheat in the exam ________ the teacher came up, smiling to him.
| A．as | B．when | C．while | D．until |