2. 职称英语
  3. Across Africa, the tsetse fly threatens a staggering 55 millions people and thei

Across Africa, the tsetse fly threatens a staggering 55 millions people and thei

游客2024-08-11  31
问题 Across Africa, the tsetse fly threatens a staggering 55 millions people and their 【M1】______
livestock. The insect sucks blood and in doing so may pass on babies or the dead 【M2】______
parasite that causes trypanosomiasis, sometimes it known as sleeping sickness. 【M3】______
Infected animals suffer of poor growth, weight loss and low milk yield. They 【M4】______
may also become fertile and die. An estimated 5000,000 people are also affected 【M5】______
by the disease each year, and most of them die. Tsetse fly traps are a simple
but effect solution. They are built using blue cloth spread between three poles, 【M6】______
that looks like a cow to the hungry insect, while bottles containing a mixture 【M7】______
of cows’ urine and acetone are placed below. Attracted by the smell, the tsetse
fly settles on the cloth but is unable to get a bite and falls into the trap. One 【M8】______
tsetse fly trap cost only ￡20 to build but tests have shown that a single trap 【M9】______
will not work. For this reason it’s important that farmers build a number traps 【M10】______
across an area. [br] 【M7】
选项
答案 that一which
解析 (此处主句后面接了一个非限制定语从句，指代前面整个句子，所以应该用关系代词which引导而不是that。)
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