Remember to do this in time of H1N1 ---         constantly the windows to let fresh air enter and move around inside, and avoiding the access to the crowds, a necessity everyday.

A．open

B．we open

C．opening;

D．to open

以下缩写是指：ODS（）.

A．气相色谱法 

B．高效液相色谱法 

C．十八烷基硅烷键合硅胶 

D．红外分光光度法 

E．差示扫描量热法