例句與造句

1. Grass and clover seed should be sown at a depth of 12-20mm .
   禾木科草和三葉草播種深度應為12-20毫米。
2. Grass and clover seed should be sown at a depth of 12 - 20mm
   禾木科草和三葉草播種深度應為12 - 20毫米。
3. It's difficult to find clover seed in a sentence. 用clover seed造句挺難的