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 .