实验中常用的枸橼酸钠的抗凝机制是
A．抑制凝血酶的活性B．防止血小板激活C．中和酸性凝血因子D．螯合血浆中的Ca2+
参考答案：D
—Sorry, I'm late.
—That's OK. You're here and that's what ________.[ ]
A. makes
B. works
C. stays
D. counts
苯酐泵抽空不会造成泄漏。
