Mark the letter A, B, C, or D on your answer sheet to show the underlined part that needs correction in each of the following questions.
Hardly did he enter the room when all the lights went out.
Giải chi tiết:
did he enter => had he entered
Cấu trúc: Hardly had S+ Ved when S + Ved/ V2 [ Ngay khi...thì...]
Biogas can be utilized for electricity production, cooking, space heating, water heating and process heating.