A:think , are
B:am thinking,are
C:thought, were
D:think, were
--- _____ once or ________ a week, I'm not sure.
— Mrs. White. She has lived in China for years. _____ Chinese is very good.
读 《口技》,结尾的“撤屏视之,一人、一桌、一椅、一扇、一抚尺而已”能否删去?为什么
完成句子。(共15分,每小题3分)
下列是取出少量固体粉末并装入试管进行加热的过程,各步操作中正确的是( )