A．Dictionaries have little effect on learning to speak English.
B．No matter what new words you meet while reading, never use dictionaries.
C．Small two-language dictionaries do little help to study English.
D．Reading Something for the first time, you'd better not use dictionaries.

A．why Mark Twain refused to buy a ticket for his friend
B．how Mark Twain and his friend traveled on the train
C．how Mark Twain's friend lost his wallet
D．a joke Mark Twain played on one of his friends