As you know, it is my duty to __________ my younger sisters from being hurt when they are in danger.
| A．prevent | B．keep | C．stop | D．protect |
Lily’s mobile phone was left in a taxi accidentally，never______again.
| A．to find | B．to be found | C．finding | D．being found |
Hearing his words，I couldn’t decide ______or remain.
| A．whether to go abroad | B．if I go abroad |
| C．if to go abroad | D．to go abroad |
The man we followed suddenly stopped and looked as if ______ whether he was going in the right direction.
| A．seeing | B．having seen | C．to see | D．to have seen |
Tom pretended______it but in fact，he knew it very well.
| A．not listen to | B．not to hear about |
| C．not to have heard about | D．not to be listening to |
Without facts，we can’t form a correct opinion，for we need to have actual knowledge______our thinking.
| A．which to be based on | B．which to base on |
| C．on which to base | D．which to base |