20世纪90年代之前,我国的长途电话网为典型的()选路网。
A.分级
B.等级
C.无级
D.多级
参考答案:A
增大Cell-specific Reference Signals Power,会()小区的覆盖范围。
Because the United States has little tin, ______ produced in the rest of the world.
A.tin is used
B.it uses tin
C.uses of tin
D.uses tin