not casual

His casual clothes were not appropriate for such a formal occasion.

他的便服,不适宜在这样正式的场合穿.

The disease is not spread by casual contact.

此病不会通过偶然接触传染。

He was wearing casual clothes, not his school ones.

他穿着他的便服, 不是他的校服.

We were there and not just as casual bystanders.

我们在那儿—不只是随意的旁观者.

She had a purposeful air, and it became evident that this was not a casual visit.

她一副无事不登三宝殿的神情，很明显，这不是一次随意造访。

Such casual dress would not be correct for a formal occasion.

这样的便服不宜在正式的场合穿.

Ellis spoke with a casual indifference that he did not feel.

埃利斯并没有察觉自己说话时的那种漫不经心.

She was making herself unnaturally casual. But he did not take her up on it.

她装出并不在乎的样子，但很不自然。不过他没有追问她。

To the casual observer (= somebody who does not pay much attention) , the system appears confusing.

乍看起来，这个系统好像条理不清。