在波长为λ的驻波中，两个相邻的波腹之间的距离为（）
A.
B.
C.
D.λ
参考答案：A
解析：
假如你叫李华，今年18岁。想利用暑假打工，你在报纸上看到了某咖啡厅的招聘广告。轻根据报纸内容写一封120词左右的求职信。
报纸广告：TEMPORARY JOB OFFER
Ｐart－ｔiｍｅ waiter/waitress
Age 18-24
To work in busy city centre café.
Must enjoy working with people
Previous experience necessary.
Good pay.
Tel. 01 222 643977.
个人信息: available during the week, friendly, helpful, three months in t he fast—food restaurant.
Dear sir,
_______________________________________________________________________________
___________________________________
Yours sincerely,
Li Hua
使钢材脆性增加的元素是（）
A.硫
B.硅
C.锰
D.铬
E.磷
