1. pin down

确定；使受约束；阻止

eg. It has taken until now to pin down its exact location.

一直到现在才确定了它的准确位置。

eg. We should use our secondary forces to pin down several enemy columns.

我们应该用助攻部队来牵制住敌人的几个纵队。

2. early stage

早期，初期

eg. But this is only at an early stage of feasibility study.

但是这仅仅处于可行性研究的初期阶段。

eg. Those initiatives are all in the early stages, and the dividends are not yet clear.

所有这些倡议目前都还处于早期阶段，以后的回报还不可知。

3. graze on

吃（牛羊等吃草）

eg. There is good grassland here for your cattle and horses to graze on.

这里有良好的草场可供你的牛马放牧。

eg. Small fish and invertebrates also graze on the plant-like organisms, and then those smaller animals are eaten by bigger ones.

小鱼和无脊椎动物也以这些植物类生物为食，然后则是众所周知的小鱼吃虾米，大鱼吃小鱼。