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问题 单项选择题

一碘量法测定水中溶解氧时，用硫代硫酸钠标准溶液滴定到溶液呈微黄色，加入1mL淀粉溶液，继续滴定至( )。

A．红色刚好褪去为止
B．黄色刚好褪去为止
C．蓝色刚好褪去为止
D．棕色刚好褪去为止

答案

参考答案：C

解析： 淀粉作为指示剂，淀粉遇I变蓝，当滴定结束时，发生的化学反应为2Na2S2O3+I2=Na2S4O6+2NaI，单质I2被Na2S2O3还原，故而蓝色退去。

选择题

国际间经济上的主要矛盾与冲突是 [ ]

A、领土争端

B、宗教问题

C、语言冲突

D、发展中国家和发达国家日益扩大的贫富差距

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填空题

Part 4


Questions 26-45


·Read the following text and decide which answer best fits each space.
·For questions 26-45, mark one letter A, B, C or D on the Answer Sheet.

Speaking Her Hind


By the time they turn 55, most Hollywood actresses see their careers start to fade. Not (26) for Susan Sarandon, who will help kick offthe fall movie season with three films.
(27) of the movies are likely to be blockbusters, but Sarandon chooses her (28) more for the stories they tell (29) for their commercial potential. "If we’re very lucky, these films will (30) questions that people will talk about," she says.
She’s done her own share of questioning, and arrived at a place in life (31) she’s not afraid to stand (32) her convictions—and then follow (33) with action. The eldest of nine children in a New Jersey Roman Catholic family, she stumbled into an acting (34) when she attended an audition with her ex-husband, Chris Sarandon. Twenty-five years and five Oscar nominations later, she (35) a Best Actress Academy Award for her role as Sister Helen Prejean in 1995’s Dead Man Waling, a searing film about capital punishment.
By (36) Sarandon was practiced at using her celebrity to (37) causes close to her heart. (38) , while presenting an award at the 1993 Oscars, she and longtime partner Tim Robbins, an actor and director, took 30 seconds of their podium time to speak on (39) of Haitian refugees with AIDS. "At the (40) of acting and activism is imagination," Sarandon says. "I’ve (41) had the ability to imagine being in someone else’s shoes."
She is a supporter of end-hunger and poverty (42) including Heifer International, Madre, and Habitat for Humanity, as (43) as the Center for Constitutional Rights. In the aftermath of September 11, she cooked for workers at Ground Zero, did benefit performances, and befriended firefighters and victims’ families.
Sarandon is (44) hands-on in the role she calls her (45) important—mother of three children.

A．timely

B．always

C．seldom

D．never
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