—Kathy and her sister are so alike.—I can’t tell one from ____.
Today,_________ rapid transportation and communication , the whole world seems to be smaller.
The government requested that all the people ___________ in any indoor public area.
Scientists study ___________ human brains work to make computer.
A girl on the bus begin to sing a pop song and soon all the other students _________.
---Why were you late for school today?----It was ________ I help catch a thief on the bus.