they arrived here ()sinse a week agoa week ago for a weeknext week
问题描述:
they arrived here ()
sinse a week ago
a week ago
for a week
next week
答
a week ago
过去时+点动词
答
sinse a week ago 用于完成时
a week ago 用于过去时
for a week 用于完成时
next week用于将来时
那你说应该选择哪个呢