You needn’t take your shoes off when you
题型:选择题
问题:
You needn’t take your shoes off when you enter someone’s house in Australia , _____ , of course , they’re very dirty .
A.before
B.since
C.when
D.unless
You needn’t take your shoes off when you enter someone’s house in Australia , _____ , of course , they’re very dirty .
A.before
B.since
C.when
D.unless