为什么要用乌金作瓦面？

Good Table Manners Manners play an important part in making a favorable impression at the dinner table. Here are some general rules： Napkin （餐巾） use The meal begins when the host unfolds his or her napkin. This is your signal to do the same， so place your napkin on your lap. Unfold it completely if it is a small napkin. Or in half， lengthwise （纵向地） ，if it is a large dinner napkin. If you need to leave the table during the meal， place your napkin on your chair as a signal to your server that you will be returning. Once the meal is over， place your napkin neatly on the table to the right of your dinner plate. Do not refold it. Use a napkin only for your mouth. Never use it for your nose， face or forehead. Use of utensils （餐具） Start with the knife， fork or spoon furthest from your plate， and work your way in， using one utensil for each course. If soup is served， remember to spoon away from yourself. This helps stop the drips. Do not put the entire soup spoon in your mouth. Instead， fill a soup spoon about 75 per cent with soup， and sip（啜饮）it from the side noiselessly. After finishing dinner， place the knife and fork parallel to one another across the plate with the knife blade facing inward toward the plate. Using your fingers Here's a list of finger foods： sandwiches， cookies， small fruits or berries with stems， French fries and potato chips， and hamburgers. Chew（咀嚼）with your mouth closed and don't make noise； don't talk with your mouth full. Bread must be broken with your hands. It is never cut with a knife. Don't pick something Out of your teeth. Instead， excuse yourself to the bathroom. If possible， try not to cough at the table. Do not put your elbows （肘） on the table. In France， it is essential to have both hands above the table at the same time. Do not put bones or anything else on the table. Things that are not eaten should be put on your plate.All of the following are finger foods EXCEPT（）.

A、soup

B、sandwiches

C、cookies

D、hamburgers

定子内径圆度，各径与平均半径之差不应大于发电机设计空气间隙值的（）。

A、±4%；

B、±10%；

C、±15%；

D、±20%；

水轮发电机主轴有何作用？

轴电流有什么危害？

检修工作如不能按计划期限完成，必须由（）办理工作延期手续。

A、工作负责人；

B、工作许可人；

C、工作成员；

D、班长;