如图，在四边形ABCD中，DC∥AB，DA⊥AB，AD=4cm，DC=5cm，AB=8cm．如果点P由B点出发沿BC方向向点C匀速运动，同时点Q由A点出发沿AB方向向点B匀速运动，它们的速度均为1cm/s，当P点到达C点时，两点同时停止运动，连接PQ，设运动时间为t s，解答下列问题：

从下面方框中选出与下列各句中画线部分意思相同或相近，并能替换画线部分的选项。

My mother usually goes to work at ____ about 7:30 in the morning,
John is a clever boy. He ____ does well in all the subjects,
Dave's father was ill two days ago, so he had to ____ take care of him at home.
Last night, Tom was not ____ in. He went to a movie with his friends.

The volunteers           a lot of help to the community for nearly ten years.