A:a≤﹣1
B:a<﹣1
C:﹣2≤a<﹣1
D:﹣2<a≤﹣1
① ____ A. cool B. autumn C. cloudy
② ____ A. sweater B. shirt C. have
③ ____ A. nice B. dress C. shorts
一小汽车从静止开始以3m/s2的加速度行驶,恰有自行车以6m/s的速度从车边匀速驶过.