Juice is a healthy drink _________ cola is not a healthy drink.
A:and
B:or
C:but
质量相等的甲、乙两车从某地同时由静止开始沿直线同方向加速运动,甲车功率恒定,乙车牵引力恒定,两车所受阻力相等且均为恒力.经过t时间,甲、乙两车速度相同,则( )
扩句
①湖面上起伏着涟漪。
②小燕子加入了盛会。
Every week he helps me____ (learn) math