简述汉代京师兵、地方兵和边兵的职能和构成。

A. Coward as he was, he ran back as soon as the enemy attacked.
B. Inasmuch as he has confessed and apologized, we will forgive him for the wrongs he has done us.
Clever as the boy was, he found some difficulty in solving the problem.
D. Men differ from brutes in that they can think and speak.

A. You are John Estes, the telephone engineer, aren"t you？
B. My friends all understand me.
C. I have no idea when she will come back.
D. I told John, who told his brother, and he told his wife.