关于水喷射泵的以下说法错误的是()。A.流速最高处在喷嘴出口 B.压力最低处在喷嘴出

题型:单项选择题

问题:

关于水喷射泵的以下说法错误的是()。

A.流速最高处在喷嘴出口

B.压力最低处在喷嘴出口

C.压力最低处在混合室进口圆柱处

D.混合室进口呈圆锥形能量损失较小

考点:海船船员考试喷射泵喷射泵题库
题型:单项选择题

五.语法填空 (15分)

Backpacking is a popular activity in the United States. Many different companies produce goods and equipment for those___1___ enjoy living for a while in nature. Several companies sell special foods, some of ___2____ have been produced using a method that removes the water. This method is called freez-drying. These meals include different foods such as meat, vegetables and rice or perhaps a ____3____ (mix) of several foods.

Hot water is added to the ___4_____ (dry) materal to replace the missing water. This produces a meal that ____5____ ready to eat. Backpackers use this method to carry food for two reasons. The food is easy to carry because it weighs a lot less ____6____ the water. And food that has been freeze-dried ___7____ (remain ) safe to eat for a long time.

Also, many companies produce special clothing for people who enjoy backpacking. Some companies make strong shoes made for walking and hiking. ____8____ make small stoves for cooking food. Other companies make small lightweight cloth tents campers can carry anywhere

____9______( convenience ). A few companies sell equipment that makes water safe to drink. And ___10______ number of companies make the backpacks that campers use to carry all this equipment.

1. _________  2. ____________  3. ______________  4. ____________  5. __________

6. _________  7. ____________  8. ______________  9. ____________  10.__________

题型:单项选择题

下列关于原子结构、元素性质的说法正确的是

A.原子结构随着元素原子序数的递增而呈周期性变化,这个规律叫元素周期律

B.第三周期元素的简单离子半径随原手序数的递增依次增大

C.第ⅦA族元素的简单阴离子还原性越强,其气态氢化物的稳定性越弱

D.16O218O2互为同位素,它们的性质基本相同

题型:单项选择题

如图所示,弹簧秤一端固定在墙壁上,另一端与小木块A相连,当用力加速抽出长木板B的过程中,观察到弹簧秤的示数为3.0N,若匀速抽出木板B,弹簧秤的示数大小(  )

A.一定大于3.0N

B.一定小于3.0N

C.一定等于3.0N

D.一定为零

题型:单项选择题

A transport layer protocol has several responsibilities, One is to create a process-to-process (program-to-program) communication; TCP uses port (11) to accomplish this. Another responsibility of a transport layer protocol is to create a (12) and error-control mechanism at the transport level.TCP uses a sliding (13) protocol to achieve flow control.It uses the acknowledgment packet,time-out,and retransmission to achieve (14) control.The transport layer is also responsible for providing a connection mechanism for the application program.The application program sends (15) of data to the transport layer.It is the responsibility of the transport layer at the sending station to make a connection with the receiver.

A.procedure

B.function

C.route

D.flow

题型:单项选择题

无线网络信号衰减是由于()

A.与访问点的距离

B.信号加密

C.移动电话干扰

D.已连接无线节点的数量

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