On time = punctual ÏÞíÞ , not late. if something happens on time, it happens at the time which was planned:

            The 11.45 train left on time. (=it left at 11.45)

           “I’ll meet you at 7.30.” “Ok, but please be on time.” (=don’t be late, be there at 7.30)

           The conference was very well organized. Everything began and finished on time.

The opposite of on time is late:

            Be on time. Don’t be late.

 

In time (for something / to do something) = soon enough

     Will you be home in time for dinner?(=soon enough for dinner)

   I’ve sent Jill her birthday present. I hope it arrives in time (for her

        birthday).(=soon enough for her birthday)

        I must hurry. I want to get home in time to see the football match on

       television.

       (=soon enough to see the football match)

    The opposite of in time is too late:

         I got home too late to see the football match.

       You can say just in time (=almost too late):

           We got to the station just in time to catch the train.

            A child ran across the road in front of the car, but I managed to stop

        just in time.

 

At the end and in the end

At the end (of something) = at the time when something ends. For example:

 at the end of the month   at the end of January     at the  end of the match

 at the end of the film      at the end of the course  at the end of the concert

           I’m going away at the end of January / at the end of the month.

      At the end of concert, there was great applause ÊÕÝíÞ .

          All the players shook hands at the end of the match.

You cannot say “in the end of something” .So you cannot say “in the end of January” or “in the end of the concert”.

The opposite of at the end is at the beginning:

   at the beginning of January     at the beginning of the concert

 

In the end = finally

We use in the end when we say what the final result of a situation was:

             We had a lot of problems with our car. In the end we sold it and

        bought another one. (=finally we sold it)

           He got more and more angry. In the end he just walked out of the  room.

          Jim couldn’t decide where to go for his holidays. He didn’t go anywhere in the end.

The opposite of in the end is usually at first:

          At first we didn’t like other very much, but in the end we became   good friends.