1、探险者们在美洲东部开辟了一片土地。

Explorers open up a piece of land in the east of America.

2、此人声称他的建议被忽视了。

The man alleged that his suggestion had been neglected.

3、我怀疑他没能有效地控制时间。

I suspect that he has failed to control his time effectively.

4、他们的努力不起作用。

Their effort is to no avail.

5、你能对这一结论发表意见吗?

Could you comment on this conduction?

6、他相信某些植物特种正受到灭绝的威胁。

He is convinced that some plant species are being threatened by extinction.