All China's major cities have good transport____(network). There are the tour buses, mini buses, taxis, as well as public buses,

    Buses in Chinese towns are always____(crowd). The fare depends on distance, and is payable to the____(conduct) of buses.

    A taxi is often ____most convenient means of travel in the City. They are available at airports, railway stations and hotels and even in urban areas. The total fare depends on the starting meter price____can range from 5 to 12 yuan, and the distance. Extra fees____(charge) for waiting and low speed driving during traffic jams. If you take a taxi after 11 pm, a 20 percent surcharge applies over the basic fare.

    The minibus is a compromise between the____ (relative) expensive taxis and full public transport. Their charge is a little more than that of the bus, about 2 yuan or more____ (depend) on distance, but it is very convenient, because it can stop____ any point you want along the route.

    Tour buses, normally ____ (equip) with air conditioning and TV, are managed by travel agencies, hotels and airports and provided for short tours, A tour guide is usually present on such buses.

以虫治虫是生态农业的重要内容，下图表示某一生系统中四种生物所含有机物的总量。假设这四种生物只构成一条食物链。请问在一段时间内，如果甲的种群数量增加，其可能引起的后果是