I could have helped her but she didn’t ask me to （help her）.应保留to,略去help her
When I have free time,I go on a long walk…..go on 从事-----
She was just about to get into sleep when the baby began to cry.
be about to do sth 正要做某事
I just couldn’t think of a way of solving the problem at that time.
这个赞同楼上的.solving 前加of 或改成to solve
The programme is being shown now.进行时的被动,即be being done