I developed very slowly and it took nearly two hundred years        I was built as an analytical machine by Charles Babbage.

The reason for his success is ______ he worked very hard.

_____ you are in a speech contest or you are giving a talk in class, a little preparation will make your presentation organized and dynamic.

 John plays basketball well，________ his favorite is badminton.

 Although he knew little about the large amount of work done in the field , he succeeded ____other more well-informed experimenters failed.