WHAT HAVE SCIENTISTS BEEN EXAMINING IN RECENT YEARS

2. - BAI KIEM TRA ANH 9 KI II LAN 1 2015 2016
BAI KIEM TRA ANH 9 KI II LAN 1 2015 2016

2. What have scientists been examining in recent years?

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D. WRITING: (2.5ms)

I. Rewrite the sentences, keep the meaning unchanged. (1.0m)