根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。
(66) When a person does a certain thing again, he is impelled(迫使) by some unseen force to do the same thing repeatedly; thus a habit is formed. Once a habit is formed, it is difficult, and sometimes impossible, to get rid of. (67)  Children often form bad habits, some of which remain with them as long as they live. Older persons also form bad habits as long as they live. Older persons also form bad habits, and sometimes become ruined by them.
(68) Many successful men say that much of their success has something to do with certain habits in early life, such as early rising, honesty and thoroughness.
Among the habits which children should not form are laziness, lying, stealing and so on. (69) Unfortunately older persons often form habits which ought to have been avoide．(70)

A．There are other habits which, when formed in early life, are of great help.

B．Whether good or not habit are, they are easy to get rid of.

C．We ought to keep from all these bad habits, and try to form such habits as will prove good for ourselves and others.

D．Habits, whether good or bad, are gradually formed.

E．It is very important for us to know why we should get used to good habbits.
F．These are all easily formed habits.
G．It is therefore very important that we should pay great attention to the formation of habits.