如图中最后一秒的加速度为____ m/s2．
They feel ____(内疚) about not being able to see their son often because they are busy with their work.
某同学在家指导妈妈“用鲜奶制作酸奶”和“用葡萄酸制葡萄酒”，下列指导措施中，正确的是（ ）
计算：（15-3）0+2sin30°-83+|-2|．
