静脉输液时，茂菲滴管内液面自行下降，其原因是

A．输液管有裂隙

B．病人肢体位置不当

C．压力过大

D．输液管口径粗

E．输液速度过快

—_______ under the table?

—No, it isn't. It's under the chair. [ ]

A. They are

B. Are they

C. It is

D. Is it