问题 多选题
如图所示,理想变压器原副线圈匝数之比为4:1,原线圈接入一电压为u=220sin100πtV的交流电源,副线圈接一个R=27.5Ω的负载电阻.则下述结论正确的是(  )

A.副线圈中电压表的读数为55V

B.副线圈中输出交流电的周期为0.01s

C.原线圈中电流表的读数为0.5A

D.原线圈中的输入功率为110W

答案

AC

不定项选择
填空题

Part 4


Questions 26-45


·Read the following passage and choose the best word for each space.
·For questions 26-45, mark one letter A, B, C or D on the Answer Sheet.
Do you want to send an e-mail message to the White House
Good luck.
In the past, (26) President Bush — or at least those assigned to read his mail — what was (27) your mind it was necessary only to sit down at a personal computer connected to the lnternet and (28) a note to president@ whitehouse.gov.
But this week, Tom Matzzie, an online organizer with the A.F.L.-C.I.O., discovered that (29) with the White House had become a bit more (30) . When Mr. Matzzie sent an e-mail protesting (31) a Bush administration policy, the message was bounced back With an automated reply, saying he had to send it again in a new way.
Under a system (32) on the White House Website (33) the first time last week, those who want to send a message to President Bush must now (34) as many as nine Web pages and (35) a detailed form that starts by asking whether the message sender supports White House policy (36) differs with it.
The white House says the new e-mail system is an effort to be more responsive (37) the public and offer the administration "real time" access (38) citizen comments.
Completing a message to the president also requires (39) a subject from the provided list, then entering a full name, organization, address and e-mail address. (40) the message is sent, the writer must wait for an automated response (41) his message, (42) whether the addressee intended to send the message. The message is delivered to the White House only after the person using that e-mail address (43) it.
"Over (44) , it’s a very cumbersome process," said Jakob Nielsen, an authority on Web design. "It’s probably designed deliberately to (45) on their e-mail.\

A.cut off

B.see off

C.dash off

D.give off