Anna waved to us as a_________ that he saw us.
Đáp án A
– signal : dấu hiệu.
Ann's encouraging words gave me _________ to undertake the demanding task once again.
In the US the first stage of compulsory education _________ as elementary education.
The local people insisted that the road_________50 cm more so that, in case of flood, they still can travel on it.