问题 问答题 简答题

浅述草鱼出血病的防治方法。

答案

参考答案:

(1)发病季节到来以前,人工注射出血病灭活疫苗或免疫组织浆。

(2)用出血病免疫疫苗浸泡当年夏花,亦有效果。

(3)采用生态防病养殖法。稀养、混养、加强管理,可以降低发病率。

(4)药物防治。先用硫酸铜全池泼洒,使池中药物浓度达到0.7g/m3,再按每万尾鱼种以500g大黄拌入饵料中投喂,6d为一个疗程,头天应加倍。

(5)发病季节每半月用二氧化氯消毒1次,用量0.5g/m3水体。

(6)聚维酮碘30g/m3水体浸浴草鱼种15~20min,可预防草鱼出血病。也可全池泼洒,用量为0.2~0.5mL/m3水体。

(7)每千克饲料中加200g黄芩、黄柏、大黄、板蓝根,再加170g食盐,拌匀后制成颗粒药饵,投喂,连喂7~10d

阅读理解

阅读理解。

     What do you know about the music called "the blues"? Do you think it is the same things as jazz? Well, in

some ways the two types of music are related, but the blues has its own history and development that is quite

different from that of jazz.

     The beginnings of the blues date back to the nineteenth century. After the Civil War, when the slaves were

free in the South, life was hard. As African Americans came together and formed their own communities, the

blues began to develop out of some of their earlier music. Songs usually expressed the feelings of their

composers (作曲家) and many were about the difficult times.

     Some people say Mississippi was the birthplace of the blues, but early blues singers were also found in

Texas, Alabama, and several other Southern states. As time passed, the blues moved north. Chicago became

an important blues center.

     What does the blues sound like? Stringed instruments, especially the guitar, are important in blues playing.

A piano is also often used. Piano players frequently get the sound they want by"crushing(挤压)" the keys, or

playing two notes not quite at the same time. Many blues songs are built around three grouped lines. The first

two lines are repeated, and then the third line is a sort of comment.

     Who were some legendary blues figures? Bessie Smith was an early female singer; Robert Johnson became

famous for his special way of playing music. Later blues greats, such as Muddy Waters, had a direct influence

on such groups as the Rolling Stones-in fact, until his death the Stones visited Muddy Waters whenever they

played in Chicago.

1. What did the blues develop from?

A. The Civil War.

B. Slaves' life.

C. African American music.

D. Composers' feelings.

2. Which place is a center for the blues?

A. Mississippi.

B. Texas. C. Alabama.

D. Chicago.

3. The underlined word "legendary" in the last paragraph probably means ______.

A. untrue

B. very famous

C. very loud

D. large

4. What is the passage mainly about?

A. The birthplace of the blues.

B. The development of the blues.

C. How the blues and jazz are similar.

D. Robert Johnson and Muddy Waters.

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