科学调查表明，科学创造的最佳年龄是（）岁。
A.20~30
B.25~30
C.25~45
D.30~40
参考答案：C
用所给词的正确形式填空。
1. My hands are ___________ (small) than his hands.
2. My pencil is shorter than ___________ (you).
3. His head is ___________ (big) than Li Ping's.
4. The dog is ___________ (heavy) than the cat.
5. My bedroom is on the ___________ (one) floor.
X线的本质是一种（）
A.光
B.射线
C.能量
D.电磁波
E.无线电波
