题干
一 Ben and Sue aren't at home, are they?
— No. They to London on business.
A：have gone
B：go
C：have been
D：will go
答案(点此获取答案解析）
A
一 Ben and Sue aren't at home, are they?
— No. They to London on business.
A：have gone
B：go
C：have been
D：will go
浓度与该醋酸中H