After Senator Smith announced that he planned to run for president, the telephone at campaign headquarters rang continuously.
Giải chi tiết:
Đáp án là B. continuously: tiếp tục >< ceasingly: tạm ngừng
Nghĩa các từ còn lại: endlessly: không ngừng; incisively: một cách sâu sắc; constantly: liên tục
Around 150 B.C. the Greek astronomer Hipparchus developed a system to classify stars according to brightness.
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.