1．The dolphin (海豚) swam so fast that it disappeared in the distance soon.
2．You have three layers of skin (皮肤), which keeps you warm or cool.
3．It is not unusual (不寻常的) for people to work 40 hours in a week.
4．She can play tennis with me and can express her emotions (感情) with words and gestures.
5．He put sugar and milk into his tea and stirred (搅动) it.
