1£®He was observed to go (go) out.

2£®As a teacher, he is respected (respect) for his good teaching.

3£®We remembered the inspiring (inspire) talks he gave us last time.

4£®China sent up two manned spaceships and they were also great scientific achievements (achieve) in the world.

5£®In order to understand the behaviour (behave) of the animal, the researcher spent many years recording its daily activities.

6£®This sentence does not seem to connect with the context.

7£®I don't know why the young couple are getting into an argument (argue)£®

8£®It is worthwhile to prepare/preparing (prepare) for the worst conditions we might meet.

9£®Only in this way can you solve this problem.

10£®She is so stubborn and once she makes up her mind, she will refuse to change it.