题干
How long______you______Tianjin?
A：have; been in
B：have; been to
C：have; gone to
D：have; been
答案(点此获取答案解析）
A
How long______you______Tianjin?
A：have; been in
B：have; been to
C：have; gone to
D：have; been
有光学活性，发生下列反应后无光学活性的是
