When it comes to the human tendency to use the right hand much more often than the left hand, we seem to have __________ it from our animal ancestors, namely monkeys and chimpanzees.
We left Xi' an _.___ a very hot summer afternoon.
The teacher is busy ____ correcting papers.
The teacher is busy ____ teaching.
____ the sun, nothing would grow.
Our bus drove ____ the Great Hall of the People.