VHFEPIRB发射的载频是()。
A、121.5MHz
B、156.525MHz
C、121.5MHz与243MHz同时或交替使用
D、243MHz
参考答案:B
The reason why John left his home was_____he felt he'd brought shame to his parents.
A.because
B.that
C.as
D.for
在下列哪种溶岩中常常可以发现化石()
A、沉积岩
B、变质岩
C、火山岩
D、侵入岩