en-, 进入，使。sure, 确认。

1. The drill should be slowly rotated to ensure a clean hole.

钻头必须缓慢转动，以保证钻孔平整光滑。

2. Goldsmith has repaired the roof to ensure the house is wind-proof.

戈德史密斯修理了屋顶，以确保房屋能够抗风。

3. An independent regulator will be appointed to ensure fair competition.

将会指定一个独立的管理机构来保证公平竞争。

4. Ensure that the frame is securely fixed to the ground with bolts.

确保用螺栓把框架牢牢地固定在地面上。

5. I have a particular responsibility to ensure I make the right decision.

我肩负特殊责任，必须确保自己作出的决定是正确的。