问题 问答题 简答题

纳豆生产中应该怎样进行接种?

答案

参考答案:

现代接种法是在60kg大豆中接入5mL~10mL培养液再装盘,最佳接种量为大豆量的1%~3%。在pH值7.0、NaCl含量2%,40℃下培养,0h~4h为纳豆芽孢杆菌的延滞期,4h~14h为对数生长期,14h~20h为稳定期,20h后为衰亡期,所以纳豆菌的最佳接种种龄是14h~20h。一般为40℃、14h~20h或38℃、20h,后熟为5℃、24h。

单项选择题
阅读理解

As we all know, it was Thomas Jefferson who wrote the Declaration of Independence (《独立宣言》). He wrote it in two weeks, and after a few changes, it was accepted by the Congress (国会). As a result, he became famous.

Born in Virginia, Thomas Jefferson, a brilliant student at school and almost talented lawyer later, was much interested in politics.

Jefferson was elected the Governor of Virginia in 1779, and he was sent to France as the representative of the American government in 1784. Sixteen years later, at the age of 57, he was elected president after Washington and Adams.

Far from a handsome man, he was tall with long arms and big hands. Jefferson, who was an amusing talker in conversation but a poor speaker, was generally good-natured.

Jefferson was regarded as a defender of freedom in America. As a president, he protected the right of free speech. Interestingly enough, in his eight years as president, Jefferson never vetoed (否决) a bill which the Congress had passed. He did a lot in organizing the new University of Virginia.

Thomas Jefferson died on July the fourth, 1826, the fiftieth anniversary of American Independence.

5. From the passage we can infer that America won its independence in _______.

A. 1786       B. 1800       C. 1842           D. 1776

6. How old was Thomas Jefferson when he became the Governor of Virgina?

A. He was 26.                         B. He was in his forties.

C. He was 36.                         D. We don’t know.

7. Which of the following statements is TRUE?

A. Jefferson wan an amusing talker, but not good at speaking in public.

B. Jefferson was not an easy person to get along with.

C. Jefferson was not only very talented but also very handsome.

D. Not being politically minded, Jefferson never vetoed a bill passed by the Congress.

4. Jefferson died when he was ________.

A. 72         B. 83           C. 73             D. 92

8. Jefferson’s greatest contribution in American history should be that ________.

A. he did a lot in organizing the new University of Virginia.

B. he was strongly against the slavery

C. he wrote the Declaration of Independence

D. he was for the right of free speech