2019年mpacc考试英语真题——连词28

{01}________ he was in the countryside, he used to take pictures of nature．
A.If
B.While
C.As long as
D.Unless
解析：if如果；while当……时候；as long as只要；unless除非。根据句意选择B项。句意为：当他在乡下时，他常拍一些风景照。
本题选B。
{02}The man is so stubborn that ________ he makes up his mind, nothing can be done to change it．
A.after
B.when
C.before
D.once
解析：从后半句来看，条件和时间意味十分强烈，只有once才能表达。
本题选D。