foil

她活泼的性格是她内向妹妹的绝佳衬托。

Her lively personality is a perfect ___foil to her shy sister.

我把食物用铝箔纸盖好再放进烤箱。

I cover the food with aluminum ___foil before putting it in the oven.

我用锡纸包住三明治，这样午餐时还是温热的。

I wrapped the sandwich in aluminum ___foil to keep it warm for lunch.