科学家计算岩石的年龄,通常根据岩石中的( )
A.铁
B.铜
C.镭
D.铅
参考答案:C
据句意及单词首字母完成句子。
1. He is h , so he will pass the exam.
2. Students are s to keep the classroom clean.
3. She didn't r home until 11:00.
4. L , he found his book that he had lost.
5. To my s , Tom did come to the party.
钩锁锁面磨修后须恢复原型,13号钩锁锁面厚度恢复至()mm。
A.76±1
B.80±1
C.82±1