氨甲苯酸
A．巨幼红细胞性贫血B．梗阻性黄疸所致出血C．缺铁性贫血D．血小板亢进症E．肿瘤放、化疗后引起的贫血
参考答案：D
Never before______ such a wonderful park, ______ I'd like to pay a visit again.
A．had I seen; where
B．have I seen; which
C．have I seen; where
D．had I seen; which
含有稀有碱基最多的RNA是
A．mRNAB．rRNAC．tRNAD．hnRNAE．snRNA
