It          me half an hour to finish the work.

—I’m sorry I ________ my exercise book at home this morning.—It doesn’t matter. Don’t forget ________ it here this afternoon.

---- How long does she read English every day? ---- She ______ half an hour _______ English every day.

--What’s wrong with you , Eric ? You look tired .--I ______ to prepare for the final exam last night .

 - Air quality in our city is becoming worse and worse. - Yes. These days' PM2.5 readings are frightening. We must do something to _______ air pollution.