有关胎心的叙述中，下列正确的是（）A、听到胎心即可确诊妊娠。 B、妊娠20周左右可以

机体嘌呤代谢障碍可引起（）。

A.皮肤卟啉病

B.皮肤淀粉样变

C.鲍温病

D.毛周角化病

E.痛风

根据短文内容，完成文后任务。注意：每个空格只填一个单词。

Jerome Kern is often called the father of American musical theater. Kern is remembered for the hundreds of songs he wrote for musical plays and movies. Music historians say that Kern gave artistic importance to American popular music for the first time. And, they say, he led the development of the first truly American theater music.

Jerome Kern was born into a middle-class family in New York City in 1885. Jerome's mother, Fanny, loved the piano. She began to teach Jerome how to play when he was very young.

Jerome was a quiet boy and not a top student. When he completed high school, his father said he would have to work in the family's store. But he later came to believe that Jerome might do better in music than in business after all. So he let the boy go to Europe to study music, as almost all serious young musicians did at the time.

Jerome Kern began his career as a songwriter in theaters in London and New York City. Success came quickly. By the early nineteen twenties, Kern was a successful young composer for Broadway musical comedies. In one three-year period alone, he wrote music for nineteen shows.

Kern wanted to try something completely new. He thought a musical play should be a real work of art, not just a collection of songs and dances. Kern wanted to do a truly American musical, with real American characters and real situations.

In 1927, he found the story he wanted. It was the book "Show Boat" by American writer Edna Ferber. "Show Boat" takes place in the 1880 on a passenger steam boat that travels along the Mississippi River.

Kern died in 1945 at the age of sixty. But "Show Boat" has been performed thousands of times

all over the world.

自动开闭器应符合下列哪些要求（）。

A.绝缘座安装牢固、完整、无裂纹

B.动接点在静接点片内的接触深度不小于5mm

C.用手扳动动接点，其摆动量不大于3.5mm

D.动接点与静接点座间隙不小于3mm

领海

2013年4月，习 * * * * 在同全国劳动模范代表座谈时强调，必须牢固树立劳动最光荣、劳动最崇高、劳动最伟大、劳动最美丽的观念，让全体人民进一步焕发劳动热情、释放创造潜能，通过劳动创造更加美好的生活。从唯物史观看，尊重劳动和劳动群众是因为（）。

①劳动是人的存在方式和社会发展的基础

②劳动贡献是衡量人的自由全面发展程度的根本尺度

③劳动群众能根据自己意愿自由地创造历史

④劳动群众的根本利益与社会发展的客观规律是一致的

A.①②

B.①④

C.②③

D.③④