问题 选择题

下列说法中错误的是(  )

A.蚯蚓可以改良土壤,有疏松泥土及增耕地肥力的作用

B.蜜蜂的采粉活动有利于植物结实,但同时也对花造成了破坏

C.一只青蛙一年能消灭一万只害虫,因此不能捕食青蛙

D.一只猫头鹰在一个夏季所消灭的鼠类,相当于增产1000千克的粮食,对人类是有益的

答案

蚯蚓对人类的益处很多,蚯蚓在土壤里活动,使土壤疏松,空气和水分可以更多地深入土中,有利于植物生长,能够起到改良土壤的作用.蚯蚓能够提高土壤的肥力,蚯蚓吃进的腐烂有机物和大量土粒,经过消化形成粪便排出体外,其中含有丰富的氮,磷,钾等养分.有些动物是人类某些害虫的天敌,它们可以对害虫的数量起到一定的控制作用.蛙类和蟾蜍类常以严重危害农作物的蝗虫、蚱蜢、黏虫等为食.鸟儿帮助我们消灭了许多害虫.自然界中的动物和植物在长期生存与发展的过程中,形成相互适应、相互依存的关系.动物能够帮助植物传粉如蜜蜂采蜜,使这些植物顺利地繁殖后代.动物能够帮助植物传播果实和种子如苍耳果实表面的钩刺挂在动物的皮毛上,有利于扩大植物的分布范围.昆虫在采食花蜜的同时,身上会不知不觉地粘上花粉,飞落在同种植物的另一朵花的柱头上,就完成了传粉.不会对花造成了伤坏.

故选:B

填空题
单项选择题

Vienna was one of the music centers of Europe during the classical period, and Haydn, Mozart, and Beethoven were all active there. As the (1) of the Holy Roman Empire (which included parts of present-day Austria, Germany, Italy, Hungary, Czech and Slovakia), it was a (2) cultural and commercial center (3) a cosmopolitan character. Its population of almost 250,000 (in 1800) made Vienna the fourth largest city in Europe. All three (4) masters were born elsewhere, but they were (5) to Vienna to study and to seek (6) . In Vienna, Haydn and Mozart became close friends and influenced each other’s musical (7) . Beethoven traveled to Vienna at sixteen to play for Mozart; at twenty-two, he returned to study with Haydn.

Aristocrats from all over the Empire spent the winter in Vienna, sometimes bringing their private (8) . Music was an important part of court life, and a good orchestra was a (9) of prestige. Many of the nobility were excellent musicians.

Much music was heard in (10) concerts where aristocrats and wealthy commoners played (11) professional musicians. Mozart and Beethoven often earned money by performing in these intimate concerts. The nobility (12) hired servants who could (13) as musicians. An advertisement in the Vienna Gazette of 1789 (14) : " Wanted, for a house of the gentry, a manservant who knows how to play the violin well. "

In Vienna there was also (15) music, light and popular in (16) . Small street bands of wind and string players played at garden parties or under the windows of people (17) to throw (18) money. Haydn and Mozart wrote many outdoor entertainment (19) , (20) they called divertimentos or serenades. Vienna’s great love of music and its enthusiastic demand for new works made it the chosen city of Haydn, Mozart and Beethoven.

9()

A.symbol

B.sign

C.sight

D.signal