Why were you late for the class, Jenny— Oh, my clock must be running slow, and it needs____.

In his book,he explains both ______ it means to be a scientist and ______ science works.

The traffic is heavy this day, I _____arrive a bit late, so could you save me a place? [ ]

The _________ of Lei Feng encourages us to serve the people all the time.

________ make another try , Ishall do everything possible to help you