At least a year's preparatory work will be necessary before building can start.

在建造开始之前至少需要一年的准备工作。

All the preparatory work has been completed.

各项准备工作均已就绪。

We'll go on with the preparatory work.

我们将继续进行筹备工作。

Suppose the preparatory work should not be completed.

假设准备工作完成不了，那可怎么办？

Have you finished the preparatory work for tomorrow's meeting?

你完成明天的会议准备工作了吗？