我在壁炉里发现了一小块煤。

I found a small ___lump of coal in the fireplace.

为了避免酱汁结块，要彻底搅拌。

To avoid ___lumps in the sauce, whisk it thoroughly.

他在人行道上发现了一块沉重的混凝土。

He discovered a heavy ___lump of concrete on the pavement.