制作口腔上皮细胞临时装片时，要用生理盐水，其作用是

A．分离口腔上皮细胞

B．保持细胞的形态

C．增强细胞活力

D．杀死细胞，便于观察

When most people refer to multimedia, they generally mean the combination of two or more continuous media, usually with some user (115) . In practice, the two media are normally audio and video, this is, (116) plus moving (117) .
It should be’ obvious by now that transmitting multimedia material in uncompressed form is completely out of (118) . The only hope is that massive compression is possible. Fortunately, a large body of research over the past few decades has led to many compression techniques and algorithms that make multimedia transmission (119) .

A．display

B．games

C．help

D．interaction

E．pictures

F．sound

G．web