最常见的深静脉血栓形成是
A.上肢深静脉血栓形成B.下肢深静脉血栓形成C.上腔静脉血栓形成D.下腔静脉血栓形成E.腋-锁骨下静脉血栓形成
参考答案:B
More highways have been built in China, ______ it much easier for people to travel from one place to another.
A.having made
B.made
C.to make
D.making
外光电效应分为光电导效应和光生伏特效应。