问题 解答题

测胸围差时,受测者要脱去外衣,取自然站立的姿势,昂首挺胸,不憋气.呼吸要均匀.______.

答案

胸围差是指尽力吸气终了时的胸围的长度与尽力呼气终了时的胸围长度的差.测量时先让受测者尽力深吸气,记录下吸气终了时的胸围长度.再让受测者尽力深呼气,记录下呼气终了时的胸围长度,计算两次胸围长度之间的差.即胸围差.

故答案为:×

单项选择题
阅读理解

阅读理解。

     We experience different forms of the Sun's energy every day. We can see its light and feel its warmth.

The Sun is the major source of energy for our planet. It causes the evaporation (蒸发) of water from the

oceans and lakes. Sunlight also provides the energy used by green plants to make their own food. These

green plants then provide food for all organisms (生物) on the Earth.

     Much of the energy that comes from the Sun never reaches the Earth's surface. It is either reflected

or absorbed by the gases in the upper atmosphere. Of the energy that reaches the lower atmosphere, 30%

is reflected by clouds or the Earth's surface. The remaining 70% warms the surface of the planet, causes

water to evaporate, and provides energy for the water cycle and weather. Only a tiny part, approximately

0.023%, is actually used by green plants to produce food.

     Many gases found in the atmosphere actually reflect heat energy escaping from the Earth's surface back

to the Earth. These gases act like the glass of a greenhouse in that they allow energy from the Sun to enter

but prevent energy from leaving. They are therefore called greenhouse gases.

     When sunlight strikes an object, some of the energy is absorbed and some is reflected. The amount

reflected depends on the surface. For example, you've probably noticed how bright snow is when sunlight

falls on it. Snow reflects most of the energy from the Sun, so it contributes to the low temperatures of winter.

Dark-coloured surfaces, such as dark soil or forest, absorb more energy and help warm the surrounding air.

1. According to the passage, the root cause for weather changes on the Earth is _____.

A. the atmosphere surrounding the Earth

B. water from oceans and lakes

C. energy from the Sun

D. greenhouse gases in the sky

2. Only a small part of the Sun's energy reaches the Earth's surface because most of it is _____.

A. absorbed by the clouds in the lower atmosphere

B. reflected by the gases in the upper atmosphere

C. lost in the upper and lower atmosphere

D. used to evaporate water from the oceans and lakes

3. We learn from the passage that _____.

A. all living things on the Earth depend on the Sun for their food

B. a forest looks dark in winter because it absorbs solar energy

C. only 0.023% of the energy from the Sun is made use of on the Earth

D. greenhouse gases allow heat energy to escape from the Earth's surface