| 1. | Often they mark the path with buoys .
他们常常用浮标作为航道的标志。 |
| 2. | Crack propagation usually begins slowly .
裂纹的增长常常是开始缓慢。 |
| 3. | They often fall out over some trifling matter .
他们常常因小事争吵。 |
| 4. | The export trade subjects to many risks .
出口贸易常常遇到许多风险。 |
| 5. | He makes mistakes , and that very often .
他犯了错误，而且是常常犯。 |
| 6. | A sick person often has fur on his tongue .
一个病人舌上常常有舌苔。 |
| 7. | She often puts in twelve hours' work a day .
她常常一天工作十二小时。 |
| 8. | Liberty often degenerates into lawlessness .
自由常常变质为无法无天。 |
| 9. | Its intensity is often somewhat diminished .
它的强度常常稍微减弱。 |
| 10. | You should always verify your references .
你要常常校准你的参考资料。 |
