A fire may be spread by which of the following means？A.Conduction of heat to adjacent surf

If there is no other way to save a()person in a tall building on fire, fire fighters may spread a net into which the person can jump.

A、volt

B、wrapped

C、trapped

D、deserted

Fire may be spread by which means？

A.Conduction of heat to adjacent surfaces

B.Direct radiation

C.Convection

D.All of the above

Which of the following is INCORRECT？

A．Hong Kong is waiting for a new visitor.

B．The red fire ants are native to South America.

C．The supply of tangerine may be affected by the infestation of red fire ants.

D．Chinese customs officers will take measures to control the spread of the insects.

A.was able to

B.could

C.had to

D.would

Non-indigenous (non-native) species of plants and animals arrive by way of two general types of pathways. First, species having origins outside the United States may enter the country and become established either as free-living populations or under human cultivation--for example, in agriculture, horticulture, aquaculture, or as pets. Some cultivated species subsequently escape or are released and also become established as free-living populations. Second, species of either U.S. or foreign origin and already within the United States may spread to new locales. Pathways of both types include intentional as well as unintentional species transfers. Rates of species movement driven by human transformations of natural environments as well as by human mobility--through commerce, tourism, and travel--greatly exceed natural rates by comparison. While geographic distributions of species naturally expand or contract over historical time intervals (tens to hundreds of years), species' ranges rarely expand thousands of miles or across physical barriers such as oceans or mountains.

Habitat modification can create conditions favorable to the establishment of non-indigenous species. Soil disturbed in construction and agriculture is open for colonization by non-indigenous weeds, which in turn may provide habitats for the non-indigenous insects that evolved with them. Human-generated changes in fire frequency, grazing intensity, as well as soil stability and nutrient levels similarly facilitate the spread and establishment of non-indigenous plants. When human changes to natural environments span large geographical areas, they effectively create passages for species movement between previously isolated locales. The rapid spread of the Russian wheat aphid to fifteen states in just two years following its 1986 arrival has been attributed in part to the prevalence of alternative host plants that are available when wheat is not. Many of these are non-indigenous grasses recommended for planting on the forty million or more acres enrolled in the U.S. Department of Agriculture Conservation Reserve Program.

A number of factors perplex quantitative evaluation of the relative importance of various entry pathways. Time lags often occur between establishment of non-indigenous species and their detection, and tracing the pathway for a long-established species is difficult. Experts estimate that non-indigenous weeds are usually detected only after having been in the country for thirty years or having spread to at least ten thousand acres. In addition, federal port inspection, although a major source of information on non-indigenous species pathways, especially for agriculture pests, provides data only when such species enter via closely-examined routes. Finally, some comparisons between pathways defy quantitative analysis--for example, which is more "important": the entry path of one very harmful species or one by which many but less harmful species enter the country？

The first pathway of a foreign species of plants to enter America is independent of human assistance.

A．True

B．False

A.flashes

B.burns

C.lights

D.sparks

The fire spread very quickly because lots of ______ had been burned.

A．oil

B．paint

C．paper

D．paper, oil and paint

The fire spread through the hotel very quickly but everyone ______ get out in time.

A．had to

B．would

C．could

D．was able to

To prevent the spread of fire by conduction, you should ______.

A.cool the bulkheads around the fire

B.remove combustibles from direct exposure

C.close all openings to the area

D.shut off all electric power