As we all know，tigers and cats________the same family of beasts.
| A．belonged to | B．are belonged to |
| C．belong to | D．are belonging to |
According to the latest research, getting enough sleep is _____to maintaining good health and reducing stress.
| A．practical | B．contradictory | C．essential | D．alternative |
In the eyes of a policeman, it's a usually very dangerous to get close to the _____criminal. He may do anything he would to escape.
| A．desperate | B．conscious | C．primitive | D．sensitive |
Nowadays, Internet shopping will really_____when people are sure that it is safe.
| A．take off | B．take up | C．take away | D．take on |
Every time I take part in a friend’s big party. I always go to talk to those who just sit alone so that they don’t feel_____.
| A．let out | B．wiped out | C．made out | D．left out |
Nokia has a family of low-cost mobile phones based on Google's Android operating system.
| A．performed | B．operated | C．launched | D．instructed |