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

在开始动工之前至少要做一年的准备工作。

...preparatory talks for this week's summit in the Maldive Islands.

为本周在马尔代夫群岛召开的峰会举行的预备会谈

Sloan cleared his throat preparatory to speaking. [+ to]

斯隆清了清嗓子，准备讲话。

She lit the oven, preparatory to putting the pie into it.

她把烤箱加热，准备把馅饼放进去。