THEY MADE AN AERIAL SURVEY; THAT IS, THEY MADE A SURVEY____________...

22. - KIEM TRA 1TIET BAI SO 1 HOC KY 2 KHOI 12 CB
KIEM TRA 1TIET BAI SO 1 HOC KY 2 KHOI 12 CB
22.They made an aerial survey; that is, they made a survey__________________________.A. by ship B. by plane C. on foot D. by telescope