A. vessel towing astern B. barge pushed ahead C. vessel towing astern only when the length of her tow exceeds 200 meters D. this signal does not exist in international water
A. “癸卯学制” B. “壬子一癸丑学制” C. “壬戌学制” D. “1951年学制&rdquo
A. 正确 B. 错误