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
Around 150 B.C. the Greek astronomer Hipparchus developed a system to classify stars according to brightness.
Biogas can be utilized for electricity production, cooking, space heating, water heating and process heating.