I couldn't have got to the meeting on time - _______ an earlier train . 

If I_____plan to do anything I wanted to ,I’d like to go to Tibet and travel through as much of it as possible 

.We were all waiting for you .You _____for the seaside by yourself without leaving a message.

He has no idea what the book is about．He        have read it very carefully．

Among the 15-year-old children, some        studying in university while others are still learning to read and write.