For most male spiders courtship is a perilous procedure, for they may be eaten by females.
Giải chi tiết:
Đáp án là C. perilous: nguy hiểm >< safe: an toàn
Các từ còn lại: complicated: phức tạp; dangerous: nguy hiểm; peculiar: kỳ dị
Population growth rates vary among regions and even among countries within the same region.
Biogas can be utilized for electricity production, cooking, space heating, water heating and process heating.
Around 150 B.C. the Greek astronomer Hipparchus developed a system to classify stars according to brightness.