一 Have you ever been to Nanjing?
一 Yes, I have. I there two years ago.
A:have been
B:have gone
C:will go
D:went
5×4-5=____ 7×6+7=____
8×4+8=____ 6×7-6=____
A.试管 B.烧杯 C.坩埚钳 D.漏斗 E.胶头滴管