确认大肠杆菌来源仍是一挑战

词汇讲解：

1. frustration n. 挫折；失败；挫败；失意；沮丧
例句：He vented his frustration on his wife.
他受到挫折却把气发泄到妻子身上。

2. germ n. 微生物; 病菌, 细菌
例句：Colds are spread by germs.
感冒由细菌传播。

3. poisoning n. 中毒
例句：Cases of plant poisoning severe enough to warrant hospital admission are rare.
植物中毒严重至必须住院治疗的病例很少见。

4. ingredient n. (混合物的)组成部分；（烹调的)原料
例句：What are the ingredients of the cake?
这蛋糕是用哪些原料做成的?

5. manufacturer n. 制造商, 制造厂，制造者，生产商
例句：The manufacturers in some countries dumped their surplus commodities abroad.
一些国家的制造商向国外倾销过剩产品。

6. provide v. 提供
例句：On Sundays his landlady provided dinner as well as breakfast.
星期天,他的女房东不但供给早餐,还供给晚餐。

7. pick vt. 挑选, 选择
例句：Dade picked a dress in fashion for his girlfriend.
达德给他的女朋友挑了一件时髦的裙子。

8. plow v. 耕,犁,犁耕
例句：Farmers now use tractors to plow their fields.
现今农民用牵引机耕地。

9. trace vt. 发现; 找到
例句：They could not trace him.
他们找不到他。

10. complication n. (新出现的)困难, 难题；〈医〉并发症
例句：Complications set in, and the patient died.
病人因出现并发症而死亡。

11. frustrating adj. 产生挫折的；使人沮丧的，令人泄气的,令人懊恼的
例句：It was a demeaning and ultimately frustrating experience.
那是一次有失颜面并且令人沮丧至极的经历。

12. senior adj. 资深的; 地位高的
例句：He is a senior member of the committee.
他是一名资深的委员。