—The guard keeps         watch at the gate.

—So he does. Only those         knows well could be let in.

A．close; who

B．tight; whom

C．tight; that

D．close; he

输液完毕，以0.4%什么溶液多少ml注入后塞住针孔：（）

A、生理盐水1—2ml

B、枸橼酸钠生理盐水2—3ml

C、0.4%枸橼酸钠生理盐水1—2ml

D、生理盐水2—3ml