醛固酮的主要作用是
A．排Na+排K+
B．保Na+保K+
C．排Na+保K+
D．保Na＋排K＋
E．保H＋排Na＋
参考答案：D
---Is that Jack speaking?
---Sorry, he _______ in. He _______ back in half an hour.
A．isn’t; will be
B．wasn’t; will
C．isn’t; is
D．wasn’t; was
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