while|Whilst

她一边走路一边唱歌。

She sings ___while walking.

虽然他很有钱，但他从不炫耀。

___While he is very rich, he never shows off.

虽然外面很冷，但屋里很暖和。

___While it is cold outside, it is warm inside.

虽然他很努力，但他的兄弟却总是偷懒。

___Whilst he works very hard, his brother always slacks off.