上塔的提馏段主要是提高氧的浓度,得到()的区间。
参考答案:高纯度氧
—Pity you missed the lecture on nuclear pollution.
—I____ it, but I was busy preparing for a job interview.
A.attended
B.had attended
C.would attend
D.would have attended
县级供电公司签约人,人要从事()工作。
A.一般用户供用电合同的审核
B.一般用户供用电合同的最终审核、签字、盖章
C.低压供电用户供用电合同的最终审核、签字、盖章
D.特殊用户供用电合同的最终审核、签字、盖章