The plant's leaves can often turn brown, and I sometimes cut off the worst offenders.

那种植物的叶子常会变成褐色，我有时会把最有问题的剪掉。

《柯林斯英汉双解大词典》

Autumn leaves begin to turn brown.

秋天的落叶开始变成褐色。

youdao

The fowls began to turn brown, and were nearly ready, but the guest had not yet arrived.

鸡开始变成棕色，差不多准备好了，但是客人还没有到。

youdao

It seemed to him that his flowers were beginning to turn brown in her hands.

VOA: special.2009.05.23

After fruits are cut and exposed to the air, they can turn brown and lose nutrients.

NPR: Grilling Your Dessert

Put them out in the more open parts of the yard and many of them would get scorched and turn brown.

WSJ: It's Better in the Shade

Landscape painters struggled with treacherous greens that turn brown and with the irksome fact that brown itself is not a natural hue (try finding it in a rainbow).

ECONOMIST: Science and history of colour