上下牙列最广泛接触时,下颌所处的位置称为()
A.颌间距离
B.垂直距离
C.息止间隙
D.息止颌位
E.正中位
参考答案:E
The bikes produced in that factory are of high quality. So they ______ well both at home and abroad.
A.sell
B.are sold
C.may be sold
D.are to be sold
自然环境对生物的生态作用是各个生态因子共同组合在一起,对生物起的综合作用。( )