问题
单项选择题
高压直流输电可能引发次同步振荡问题，是由于HVDC（通常是整流侧）控制系统与汽轮发电机组（）相互作用，在特定条件下会对某些模式的扭振起到加强作用。
A.汽缸
B.轴系
C.调速器
D.其他三个选项都不是
答案
参考答案：B
搜题请搜索小程序“爱下问搜题”
高压直流输电可能引发次同步振荡问题，是由于HVDC（通常是整流侧）控制系统与汽轮发电机组（）相互作用，在特定条件下会对某些模式的扭振起到加强作用。
A.汽缸
B.轴系
C.调速器
D.其他三个选项都不是
参考答案：B
| 完形填空。 In America, on school and work days, breakfast in most homes is often a hurried meal. Some people even don't have it in order to 1 work or school on time. Others just stop at coffee shops for coffee. But on weekends, 2 are quite different. People usually get up late, so they have enough time to have a large breakfast. Lunch is just a 3 break from the day's work rather than a large, long meal. It usually lasts 4 half an hour or an hour, so family members do not have time to 5 home. Most people have a sandwich or a hamburger, and fruit or ice-cream for lunch. 6 people either take their lunches to work in the brown paper "lunch bag", 7 eat a sandwich at a fast food restaurant. Children 8 to bring the "lunch box". Dinner is the most 9 meal of the day in the USA. At this meal, most American families can sit down together. It is usually a hot, large meal and it is quite different from lunch. 10 usually cooked dinner for their families in the past. Nowadays, however, with more women working and as a result, men are doing more in the kitchen. | ||||
|