I don't like plain chocolate.

我不喜欢吃黑巧克力。

"Have you got just plain chocolate?"—"No, I'm afraid there's not much call for that."

“有纯巧克力吗？” — “没有，恐怕对这种巧克力的需求不多。”

However, at first only plain chocolate (a kind of chocolate without milk and with very little sugar) was produced.

但是，一开始仅生产不添加牛奶，少糖的原味巧克力。

Have you got just plain chocolate?

你们有纯巧克力吗？

We were offered a selection of milk and plain chocolate.

有人给我们精选的牛奶巧克力和纯巧克力。