电可调天线指的是可以调节天线的（）
A、方位角
B、天线的增益
C、天线的极化方式
D、天线的下倾角
参考答案：D
He was not really in the mood for anything ______ it dawned on him that it had not been his fault.
A．since
B．when
C．after
D．until
说明混凝土构件蜂窝麻面的产生原因，并指出预防措施。
