2017年7月22日北京鼎均gre作文机经（七）.

　　考试时间:2010/7/22

　　考试地点:北京鼎钧大厦

　　ISSUE题目: 168 --"Critical judgment of work in any given field has little value unless it comes from someone who is an expert in that field."

　　Argue题目: 47--Scientists studying historical weather patterns have discovered that in the mid-sixth century, Earth suddenly became significantly cooler. Although few historical records survive from that time, some accounts found both in Asia and Europe mention a dimming of the sun and extremely cold temperatures. Either a huge volcanic eruption or a large meteorite colliding with Earth could have created a large dust cloud throughout Earth&aposs atmosphere that would have been capable of blocking enough sunlight to lower global temperatures significantly. A large meteorite collision, however, would probably create a sudden bright flash of light, and no extant historical records of the time mention such a flash. Some surviving Asian historical records of the time, however, mention a loud boom that would be consistent with a volcanic eruption. Therore, the cooling was probably caused by a volcanic eruption.