She ______ in vain to get onto the crowded bus and had to wait for the next one and risk being late for work.
A. tested
B. fought
C. tried
D. managed
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What day does that magazine _______?
A.come across
B.come out
C.come off
D.come about
Peter took up the rear, armed with a large hammer _____ emergencies.
A.in that case of
B.in any case of
C.in case of
D.in the case of
严格检查冷却设备的密闭性,不允许物料窜入冷却剂中,也不允许冷却剂窜入被冷却的物料中,特别是____。
A. 有毒气体
B. 碱性气体
C. 酸性气体
D. 可燃气体
腐蚀性试验项目中Cl-的试验方法是()。
A. 电位法
B. EDTA容量法
C. 摩尔法
D. 酸滴定法