出现译成英语?

你好！

按照你所给的句子和语境，里面的【形成】可以用下面这些词来表达——

form

take form/take shape

appear /occur

划线句子可以翻译为——

The lowest temperature is in the early morning ,so heavy fog is often formed

in the morning .

or

In the early morning ,the temperature reaches the lowest,as a result ,heavy

fog often takes form/shape in the

morning .

or

The temperature becomes the lowest

in the early morning ,therefore,heavy

fog often appears/occurs in the

morning .

这里的“出现”动词，可以有多种的表现单词：如appear（显现），form（形成），occur（发生）等。