函数f（x）=x+2的零点是（ ）
A．1
B．-2
C．3
D．4
解；由f（x）=x=2=0可得x=-2
故选B
When he was young， he used to hard at his lessons.
A．devote to working
B．devote himself to work
C．be devoted to work
D．be devoted to working
甘遂内服时用量是（）
A.0.01～0.05g
B.0.5～1g
C.2～6g
D.10～15g
E.30～60g
