The chemistry teacher required the students___more attention___the lab clean
.On hearing the _________ voice, the little girl became _________.
.—___________ is the population of the United States?—I don’t know exactly, but I’m sure that it has __________ population than China.
.. —I’m afraid I have to leave for New York tomorrow. —_____
.I’m taking these apples out of the bag to _____ the load I have to carry.
.At the same time, they are taking strong _______to protect the wild animals.