She wrote me a vicious letter.
Giải chi tiết:
Ta hiểu trong câu này "vicious": thô thiển, bất lịch sự
A. có ích
B. nhã nhặn, lịch sự
C. nguy hiểm
D. khoẻ
Biogas can be utilized for electricity production, cooking, space heating, water heating and process heating.
Population growth rates vary among regions and even among countries within the same region.
Around 150 B.C. the Greek astronomer Hipparchus developed a system to classify stars according to brightness.