1. Kaz's father had been out back weeding the vegetables in his underclothes.
    和子的父亲穿着内衣裤在屋外后院的菜地里除草。

2. After I had stacked my shirts and underclothes in two empty drawers,
    我将衬衫、内衣放进两个空抽屉里，

3. I had stacked my shirts and underclothes in two empty drawers.
    我把衬衫和内衣塞进两个抽屉。