问题 问答题 简答题

影响水稻白叶枯病发生的原因有哪些?

答案

参考答案:

此病的发生与流行主要取决于品种的抗病性、气候因素、栽培条件与耕作措施。

(1)品种的抗病性:一般糯稻抗病性最强,粳稻次之,籼稻最弱。苗越小越抗病,分蘖前抗病。

(2)气候条件:此病的发生一般在气温25-30ºC最盛,适温、多雨和日照不足有利于发病。特别是暴雨或洪涝有利于病菌的传播和侵入,更易引起病害的爆发流行。

(3)耕作与栽培措施:栽培管理方面,以肥、水管理对白叶枯病影响最大。氮肥施用过多或过迟,均可导致抗病力减弱。同时造成郁闭高湿适合于发病的小气候,加重发病。深水灌溉或稻株受淹,加重发病。大水漫灌、串灌可促使病害扩展与蔓延。

阅读理解

Usually, when your teacher asks a question, there is only one correct answer. But there is one question that has millions of correct answers. That question is “What’s your name?” Everyone gives a different answer, but everyone is correct.

Have you ever wondered about people’s names? Where do they come from? What do they mean?

People’s first names, or given names, are chosen by their parents. Sometimes the name of a grandparent or other member of the family is used. Some parents choose the name of a well-known person. A boy could be named George Washington Smith; a girl could be named Helen Keller Jones.

Some people give their children names that mean good things. Clara means “bright”; Beatrice means “one who gives happiness”; Donald means “world ruler”; Leonard means “as brave as a lion”.

The earliest last names, or surnames, were taken from place names. A family with the name Brook or Brooks probably lived near a brook (小溪); someone who was called Longstreet probably lived on a long, paved road. The Greenwood family lived in or near a leafy forest.

Other early surnames came from people’s occupations. The most common occupational name is Smith, which means a person who makes things with iron or other metals. In the past, smiths were very important workers in every town and village. Some other occupational names are: Carter—a person who owned or drove a cart; Potter—a person who made pots and pans.

The ancestors of the Baker family probably baked bread for their neighbors in their native village. The Carpenter’s great-great-great-grandfather probably built houses and furniture.

Sometimes people were known for the color of their hair or skin, or their size, or their special abilities. When there were two men who were named John in the same village, the John with gray hair probably became John Gray. Or the John who was very tall could call himself John Tallman. John Fish was probably an excellent swimmer and John Lightfoot was probably a fast runner or a good dancer.

Some family names were made by adding something to the father’s name. English-speaking people added –s or –son. The Johnsons are descendants of John; the Roberts family’s ancestor was Robert. Irish and Scottish people added Mac or Mc or O. Perhaps all of the MacDonnells and the O’Donnells are descendants of the same Donnell.

小题1: Which of the following aspects do the surnames in the passage NOT cover?

A.Places where people lived.

B.People’s characters.

C.Talents that people possessed.

D.People’s occupations.小题2:According to the passage, the ancestors of the Potter family most probably _______.

A.owned or drove a cart

B.made things with metals

C.made kitchen tools or containers.

D.built houses and furniture.小题3:Suppose an English couple whose ancestors lived near a leafy forest wanted their new-born son to become a world leader, the baby might be named ________.

A.Beatrice Smith

B.Leonard Carter

C.George Longstreet

D.Donald Greenwood

问答题 简答题