问题 选择题

贮藏蔬菜、水果要保持低温,这是因为(  )

A.温度低,减少细菌病害

B.温度低,呼吸作用弱,有机物消耗少

C.温度低,促进光合作用积累

D.温度低,蒸腾作用弱

答案

温度:温度能影响呼吸作用,主要是影响呼吸酶的活性.一般而言,在一定的温度范围内,呼吸强度随着温度的升高而增强. 根据温度对呼吸强度的影响原理,在生产实践上贮藏蔬菜和水果时应该保持低温,使蔬菜、水果的呼吸作用减弱,以减少呼吸作用对有机物的消耗、可延长保鲜时间.

故选:B.

单项选择题

阅读下列短文,从每题所给的四个选项(A、B、C和D)中选出最佳选项,并在答题卡上将该项涂黑。

D

The meaning of silence varies among cultural groups. Silences may be thoughtful, or they may be empty when a person has nothing to say. A silence in a conversation may also show stubbornness, or worry. Silence may be viewed by some cultural groups as extremely uncomfortable; therefore attempts may be made to fill every gap(间隙)with conversation. Persons in other cultural groups value silence and view it as necessary for understanding a person's needs.

Many Native Americans value silence and feel it is a basic part of communicating among people, just as some traditional Chinese and Thai persons do. Therefore, when a person from one of these cultures is speaking and suddenly stops, what maybe implied(暗示) is that the person wants the listener to consider what has been said before continuing. In these cultures, silence is a call for reflection.

Other cultures may use silence in other ways, particularly when dealing with conflicts among people or in relationships of people with different amounts of power. For example, Russian, French, and Spanish persons may use silence to show agreement between parties about the topic udner discussion. However, Mexicans may use silence when instructions are given by a person in authority rather than be rude to that person by arguing with him or her. In still another use, persons in Asian cultures may view silence as a sign of respect, particularly to an elder or a person in authority.

Nurses and other care-geivers need to be aware of the possible meanings of silence when they come across the personal anxiety their patients may be expericencing. Nurses should recognize their own personal and cultural construction of silence so that a patient’s silence is not interrupted too early or allowed to go on unnecessarily. A nurse who understands the healing(治愈) value of silence can use this understanding to assist in the care of patients from their own and from other cultures.

What may be the best title for the text?()

A.SoundandSilence

B.WhatItMeanstoBeSilent

C.SilencetoNativeAmericans

D.SpeechIsSilver;SilenceIsGold

单项选择题