目前农药残留量的测定中,常用的方法是气相色谱法或气-质联用法。
参考答案:对
I was doing my homework in my bedroom _______the light went out. I did it with a candle on.
A.which
B.while
C.when
D.where
设置网页名称的标签是()
A.<titles>和</titles>
B.<name>和</name>
C.<head>和</head>
D.<title>和</title>