Heavy curtains blocked out the sunlight. 厚厚的窗帘挡住了阳光

这里heavy 改为thick 同样是正确的。只不过把 heavy 译为“厚重”似乎更好一些。

【更多例句】

He pulled the thick curtains together, leaving just a narrow gap.

他拉上厚厚的窗帘，仅留下一条狭窄的缝隙。---柯林斯例句库

 I would even request you to have a thick curtain put up between the two walls so

that either of us cannot see the other. 我甚至愿意请求你在两堵墙之间挂上厚厚的帘子，这样我们俩彼此都不能看见对方。