诊断有机磷杀虫药中毒时，全血胆碱酯酶活性应( )
A．≤90%B．≤80%C．<100%D．≤75%E．≤70%
参考答案：E
Considering his health, I advise him to ______ an hour or two each day to work out.
A．set about
B．set off
C．set up
D．set aside
工程建设监理招标( )。
A．只能编制一个标底B．能编制多个标底C．不编制标底D．标底价格与投标者商定
