下列仪器中,能直接在酒精灯火焰上加热的是
A.烧杯
B.试管
C.集气瓶
D. .
B,蒸发皿.
简述全口义齿的固位原理。
She's having a lot of trouble with the new computer, but she doesn't know whom to _____. [ ]
A. turn to
B. look for
C. deal with
D. talk about