▲表示“按时”“ 按照时间表”，英语可以用 on schedule，但不能用by schedule。如：

The project is right on schedule. 项目刚好按计划进行。

The school bus arrived at school on schedule. 校车按时来到学校。

a project that is ahead of / on / behind schedule 提前（按期 / 未按期）完成的计划

▲比较：

1. according to schedule 按计划

Everything went according to schedule. 一切都按计划进行。

Everything is going according to schedule. 一切都在按预定计划进行。

2. as scheduled 按计划

As scheduled they met on January 20. 他们按照计划在一月二十日碰了头。

As (it is) scheduled they met on January 20. 他们按照计划在一月二十日碰头。