unit 5 canada—“the true north” section c using language 题组ⅰ ⅰ.单项填空 1. —how much farther shall we have to go? —another five miles until we reach the mountain _________. a. at a distance b. in a distance c. at distance d. in the distance 2. evidence gained from observation and experiment is often used to _________ a scientific theory. a. confirm b. concern c. consult d. combine
