If we ___________some measures, we might have prevented the environmental pollution.
--- I saw Nancy on the way home yesterday. --- It be her. She’s gone to America for further study.
The walkman I bought yesterday is quite different from _______ you bought last month
Only then _____ how much damage had been caused.
As we all know,dark glasses can ________ the eyes from strong sunlight.
How the big forest fire has remains to be a mystery.