ACC电路是根据（）来调整色度信号的大小的。
A．色度信号的幅度
B．色同步信号的幅度
C．行同步信号的幅度
D．场同步信号的幅度
参考答案：B
The two things _______they felt very proud were Jim’s gold watch and Della’s hair.
A．about which
B．of which
C．in which
D．for which
组成蛋白质的主要元素不包含下列哪种元素（）。
A.C
B.0
C.F
D.H
E.N
