简述田间检验的原则。

题型:问答题 简答题

问题:

简述田间检验的原则。

考点:种子检验员考试扦样员扦样员题库
题型:问答题 简答题

下列关于DNA和蛋白质提取与分离实验的叙述,正确的有[ ]

A.提取细胞中的DNA和蛋白质都需用蒸馏水涨破细胞

B.用不同浓度NaCl溶液反复溶解与析出DNA可去除蛋白质

C.蛋白质提取和分离过程中进行透析可去除溶液中的DNA

D.蛋白质和DNA都可以用电泳的方法进行分离纯化

题型:问答题 简答题

某设备账面固定资产原值为100万元,折旧年限10年,按双倍余额递减去计算,设备开始使用第二年的折旧额为( )万元。

A.10.24

B.12.80

C.16.00

D.20.00

题型:问答题 简答题

以下关于删除数据库的叙述中,______是正确的。

A.删除数据库文件前必须先关闭数据库

B.删除数据库文件前必须先删除表文件

C.删除数据库文件前必须先将表文件移出

D.只能使用命令法删除数据库文件

题型:问答题 简答题

公安工作在战略战役部署与实施上,在法制与政策的结合上,在多部门横向协同上,要高度统一,又要注意适当分散。 ( )

题型:问答题 简答题

Visitors to Britain may find the best place to sample local culture is in a traditional pub. But these friendly hostelries can be minefields of potential gaffes for the uninitiated.
An anthropologist and a team of researchers have (1) some of the arcane rituals of British pubs—starting with the (2) of getting a drink. Most pubs have no waiters—you (3) to go to the bar to buy drinks. A group of Italian youths (4) for 45 minutes before they realized they would have to (5) for their own. This may sound inconvenient, but there is a (6) purpose.
Pub culture is designed to (7) sociability in a society known for its reserve. Standing at the (8) for service allows you to chat with others (9) to be served. The bar counter is possibly the only (10) in the British Isles in which friendly conversation with (11) is considered entirely appropriate and really quite normal (12) . "If you haven’t been to a pub, you (13) been to Britain." This tip can be found in a (14) , Passport to the Pub: The Tourists’ Guide to Pub Etiquette, a (15) code of conduct for those wanting to sample "a central part of (16) life and culture". The trouble is that if you do not (17) the local rules, the experience may fall flat. For (18) , if you are in a big group, it is best if only one (19) two people go to buy the drinks. Nothing irritates the (20) customers and bar staff more than a gang of strangers blocking all access to the bar while they chat and dither about what to order.

更多题库