The tomatoes became shriveled after being sunburned for too long.

sunburned 是动词 sunburn 的过去分词形式。sunburn 由 sun（太阳）和 burn（灼烧）组成，字面意思是"被太阳灼伤"，指植物或皮肤因过度暴露在阳光下而受损。这里指西红柿因暴晒导致表皮脱水萎缩。