Nowadays meteorologists（气象学家）can make good forecast for 3 or 5 days. Perhaps soon they may be able to do that for a week or ________.

1. A.
   more ahead
2. B.
   more behind
3. C.
   less ahead
4. D.
   less behind

Nowadays meteorologists（气象学家）can make good forecast for 3 or 5 days．Perhaps soon they may be able to do that for a week or          ．

A．more ahead          B．more behind         C．less ahead              D．less behind