56（）

.Many people don’t know that_____.

• A、twins understand each other very well

• B、twins are slow to learn to talk

• C、twins are unlikely to do less well at school than other children

• D、there exists more communication between twins

If the whole operation_____ before hand, a great deal of time and money would have been lost.

• A、was not planned

• B、has not been planned

• C、had not been planned

• D、were not planned