国际航行的船舶发出三长声表示有人右舷落水。

用户A通过计算机网络向用户B发消息，表示自己同意签订某个合同，随后用户A反悔；不承认自己发过该条消息。为了防止这种情况，应采用

A．数字签名技术

B．消息认证技术

C．数据加密技术

D．身份认证技术

《国家重点生态功能保护区规划纲要》的基本原则是( )。

A．保护优先，限制开发

B．统筹规划，分步实施

C．高度重视，精心组织

D．避免重复，互为补充

幼儿教师在示范时往往采用“镜面示范”，原因是（）

A.幼儿是以自身为中心来辨别左右的

B.幼儿好模仿

C.幼儿分不清左右

D.幼儿看得更清

How many of us would temp for three years while we waited for the perfect job Not many of us, perhaps. But Wentworth Miller, the "Prison Break" star, said he chose to wait even longer time (1) he found the right job.
"Actually I think it might have been three or four years until I was lucky enough to get guest (2) on TV shows," said Miller, 34, who rose to international stardom (3) to "Prison Break" in 2006. That kind of patience and p will was portrayed in "Prison Break". Miller (4) engineering wizard Michael Scofield, who tries everything to break out of a Chicago (5) with his brother. Miller said he was fond of his character, (6) he said "exists in shades of grey".
Miller comes from a (7) of teachers. He said he didn’t seem fated for a career in the arts, (8) his passion for acting. After (9) from Princeton with an English degree, he moved (10) his parents’ request to Los Angeles to look for a stable life. He started (11) in a little company that made television movies. This (12) simply faxing, filing, walking the boss’ dog and going to the store for the boss’ lunch. Every weekend during the summer, Miller (13) go to the office (14) he didn’t have air-conditioning. "I would hang (15) in the conference room and set up camp and rob the company kitchen," recalled Miller.
(16) , Miller realized he still had questions about his choice. He decided to quit. But the boss said he was making a mistake and offered him a well-paid assistant position. "I eventually (17) that if I did the corporate job, it would be great if I was successful, but I would always wonder about the (18) . If I did the acting and was successful, I would never wonder (19) that job," he explained. He quit and temped (20) many people in the entertainment industry.
Now, he’s a hot star and has people coming up to him at film festivals saying, "Weren’t you the one who (21) to stand by the copy machine "
"That was tough, but I’m glad I have that perspective. Because now I’m at a point (22) big shots laugh at all my jokes and I think, You know, I got coffee for people like you for six years’. So I know what’s (23) , because I’ve seen the other side." But what if, when he was offered the corporate job, there had been more money "It was never about the (24) There’s a kind of excitement that comes along with acting. I can’t find it anywhere else. Even if I had to go back to temping, even if this is not the beginning of an amazing career, I would not (25) making that jum
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房屋所有权人张某和承租人王某签订了《房屋租赁合同》，合同约定房屋的租赁期为25年。该房屋租赁合同约定的租赁期的效力为（）。

A、效力待定

B、无效

C、20年内有效，超过20年的部分，无效

D、有效