高效液相色谱法分析水中酚类化合物时,水样经树脂吸附后,应在()d内进行分析。
A.7
B.14
C.40
参考答案:C
It is usually warm in my hometown in March, but it _____ be rather cold sometimes.
A.must
B.can
C.should
D.would
列车冒进进站(进路)信号停车后,司机不得移动列车,待查清情况后,具备接车条件时,由车站以什么方式接入站内停车或通过?