I didn't know you were coming, so I didn't wait for you.

If she__________a car, she would go out in the evening.

The bones of mammals, not alike those of other vertebrates, show a high degree of differentiation.

Only a few mineral can resist weathering by rainwater, which is a weak acid.

A number of wildlife reserves have been established__________endangered species can have a

chance to survive and develop.

During the week of national tourism festival, we had visitors__________from all over the country.

The price of petrol has raised so rapidly that we decided to use the bus.

The headmaster, together with the teaching staff, are away on holiday