搜题请搜索小程序“爱下问搜题”
问题
单项选择题
核酸对紫外线的最大吸收峰是
A．220nm
B．240nm
C．260nm
D．280nm
E．300nm
答案
参考答案：
C
选择题
Everyone has periods in their lives _____ everything seems very hard.
A. when
B. where
C. which
D. that
查看答案
问答题 简答题
道岔设置几对位移观测桩？如何设置？
查看答案
