Tom, clean up the broken glass _________ someone walks on it.
Jack, look! Everybody is doing homework quietly. ________ you make a noise in class?
_______ they looked, they saw nothing but ruins after the terrible earthquake.
- Was it because of his laziness_______ he didn't do the experiment successfully?- No, it was because of his carelessness.
The volunteers will visit the primary school next Monday ,_______all the students are children of migrant workers,
Children of this age should be reminded of________ to do in public places.