4、 In saying that ephemerals will develop "vigorously" when there is favorable precipitation, the author means that their development will be
sudden
early
gradual
strong
healthy
PARAGRAPH 4
The perennial vegetation adjusts to the aridity by mear of various avoidance mechanisms. Most desert plants are 11 probably best classified as xerophytes. They possess drought-resisting adaptations: loss of water through the leaves is reduced by means of dense hairs covering waxy leaf surfaces, by the closure of pores during the hottest times to reduce water loss, am by the rolling up or shedding of leaves at the beginning of the dry season. Some xerophytes, the succulents (including cacti), store water in their structures. Another way of countering drought is to have a limited amount of mass above ground and to have extensive root networks below ground. It is not unusual for the roots of some desert perennials to extend downward more than ten meters. Some plants are woody in type — an adaptation designed to prevent collapse of the plant tissue when water stress produces wilting. Another class of desert plant is the phreatophyte. These have adapted to the environment by the development of long taproots that penetrate downward until they approach the assured water supply provided by groundwater. Among these plants are the date palm, tamarisk, and mesquite. They commonly grow near stream channels, springs, or on the margins of lakes.
5、The word "countering" in the passage is closest in meaning to
eliminating
making use of
acting against
experiencing
6、According to paragraph 4, some desert plants with root systems that are extraordinarily well developed have
relatively little growth aboveground
very leafy aboveground structures
nonwoody plant tissue resistant to wilting
water stored within their roots
7、The word "assured" in the passage is closest in meaning to
pure
diminished
guaranteed
deep
8、What do "the date palm, tamarisk, and mesquite" have in common?
They are always found together.
They depend on surface water provided by streams, springs, and lakes.
They are phreatophytes.
Their roots are capable of breaking through hard soils
PARAGRAPH 5
Animals also have to adapt to desert conditions, and they may do it through two forms of behavioral adaptation: they either escape or retreat. Escape involves such actions as aestivation, a condition of prolonged dormancy, or torpor, during which animals reduce their metabolic rate and body temperature during the hot season or during very dry spells.
9、 Which of the sentences below best expresses the essential information in the highlighted 1 sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.
One way animals escape is by entering a state of extended dormancy, known as aestivation, during the hottest and driest times of year.
Animals can escape without using direct action, or aestivation, simply by reducing their metabolic rate and body temperature.
The actions that an animal uses to escape are known as aestivation, which sometimes involves a reduction in metabolic rate or body temperature.
When the weather is especially hot and dry, an animal may suffer from a condition known as aestivation, at which point the animal needs to escape.
10、It can be inferred from paragraph 5 that all of the places desert animals retreat to
provide shade from the sun
sometimes become crowded
are places where supplies of food are plentiful
leave the animals vulnerable to predators
