1£®When hearing the news that Typhoon was coming£¬many people felt frightened(frighten)£®

2£®The teacher gave a clear explanation(explain) on the use of the word.

3£®Frank insisted that he was(be) not asleep although I had great difficulty in waking him up.

4£®I was so annoyed(annoy) that I decided to write a letter to the newspaper to discover the truth.

5£®You are fortunate to have had the help and guidance(guide) of such a man.

6£®To cut down PM 2.5 is a tough task.Cities have to consider economic development while dealing(deal) with air pollution.

7£®Parents who tend to sing(sing) to their children may help children’s development of language skills.