主要通过超导电缆来实现，且载流能力强，损耗低和体积小的技术或装置是（ ）

We students should study hard.

未知题型We students should study hard.

PN结的开关速度越快越好

未知题型PN结的开关速度越快越好

We should and study hard and prepare for the bright fut...

未知题型We should and study hard and prepare for the bright future!