身高的生长发育以生后第一年速度最快。()
参考答案：对
At first the experiment went on well, but ________ problems we hadn't expected turned up later and
it failed.[ ]
A. outstanding
B. curious
C. powerful
D. various
决定元素化学性质的是
A．质子数
B．中子数
C．电子数
D．最外层电子数
