中度有机磷中毒时的胆碱酯酶活性低于参考值的()。
A.80%~90%
B.70%~80%
C.50%~70%
D.30%~50%
E.20%~30%
参考答案:D
If there were no automatic washing machines, people would have to wash their clothes ______ hand or ______ hand-operated machines.
A.by; by
B.with; with
C.on; with
D.by; with
肿瘤的分级依据是()
A.肿瘤体积的大小
B.肿瘤的生长速度
C.肿瘤细胞的分化程度
D.肿瘤是否有转移
E.肿瘤异型性的大小