四频手机可在哪些频段间切换?()
A.850兆赫;
B.900兆赫;
C.1800兆赫;
D.1900兆赫。
参考答案:A, B, C, D
After supper,I often go for a walk ______the river near my house.
A.on
B.along
C.in
D. with
什么是精进根?