The word "that" is often used at the beginning of a clause.

Examples below show how to use "that":

I think that it's a good idea.

She was angry that her friend lied to her.

We heard that U2 will be here in June.

Note: "That" is not always necessary to use in the clause. All of the above sentences do not require "that"; however, it's important for beginning and intemediate learners of English to practice.

Do you see and hear the differences in the sentences below?

I think it's a good idea.

She was angry her friend lied to her.

We heard U2 will be here in June.

She thinks that it's important to learn English.

or

She thinks it's important to learn English.

This young woman is glad that the water is warm.

or

This young woman is glad the water is warm.