In object-oriented (51) , objects can be viewed as reusable components, and once the programmer has developed a (52) of these components, he can (53) the amount of new coding required. But (52) a (54) is no simple task because the integrity of the Original software design is critical. Reusability can be a mixed blessing for user, too, as a programmer has to be able to find the object he needs. But if (55) is your aim, reusability is worth the risk.

（51）是（）

A.complexity

B.creating

C.indisposing

D.library

E.maximize

F.minimize

G.reading

H.procedure

I.productivity

J.programming

K.security

L.using

可转换证券实际上是一种普通股票的( )

A．长期看涨期权

B．长期看跌期权

C．短期看涨期权

D．短期看跌期权