题目内容

Conversation:What luggage does Mr. Brown have?[音频]

A small suitcase and a box with tools.
B. A small suitcase with some products.
C. A small box with some documents.
D. A small suitcase and a box with some products.

查看答案

搜索结果不匹配？点我反馈

更多问题

Passage:[音频]I arrivedin plenty of time and, but I only had one small suitcase, so Idecidedto take it on the plane as. While I was sitting there drinking andreading, I wasn't aware of a woman and her child at the next table. Idid notthem and when was called, I reached for my suitcase and left.

汽蚀比转速反映了泵的抗汽蚀性能,而且()

A. 汽蚀比转速越大,泵的抗汽蚀性能越好
B. 汽蚀比转速越大,泵的抗汽蚀性能越差
C. 汽蚀比转速大小,与泵的抗汽蚀性能无关
D. 以上都不正确

托马(Thoma)汽蚀系数反映了泵的抗汽蚀性能,而且()

A. 托马(Thoma)汽蚀系数越大,泵的抗汽蚀性能越好
B. 托马(Thoma)汽蚀系数越大,泵的抗汽蚀性能越差
C. 托马(Thoma)汽蚀系数大小,与泵的抗汽蚀性能无关
D. 以上都不正确

通常水泵的进口管路比出口管路直径大一些,目的是()

A. 减小进口管路的阻力损失,增大必需汽蚀余量
B. 提高进口流体的流动速度,减低必需汽蚀余量
C. 减小进口管路的阻力损失,增大有效汽蚀余量
D. 增大进口管路的阻力损失,增大有效汽蚀余量