波长在()nm范围内的光称为X射线。
A、0.01~10
B、200~400
C、400~500
D、500~700
参考答案:A
如果log2x+log2y=1,则x+2y的最小值是______.
– Hello, could I speak to Don please? -()
A.Who are you
B.Who’s speaking
C.Are you Jane