相控整流电路按其组成器件可分为()和()两种形式。
从晶闸管开始承受正向电压到施加触发脉冲导通为止的电角度,称为()或()。
1945年8月6日和9日,()在日本广岛和长崎投放代号为“小男孩”和“胖子”两枚原子弹,迫使日本于8月15日宣布投降。
A. 俄国
B. 英国
C. 法国
D. 美国
Complete the sentences with the correct name from the reading.1._____________made $15,000 her first year.2.helped 60 couples find each other.3.didn’t do well in school as a child.4.has the same job she had 40 years ago.5.is studying to get better skills.6.loves teaching.7.studied and practiced for her job for two years.8.is in charge of a video business.