名词从句作动词宾语时，前面的that常被省略，特别是在非正式语体中：

I suggested (that) they should drive along the coast. 我建议他们沿着海岸开车。

I hoped (that) I would / should succeed. 我曾希望我会成功。

I know (that) he will be in time. 我知道他会赶得上的。

I knew (that) he would be in time. 我当时知道他会赶得上的。

He thinks (that) they will give him a visa. 他想他们会给他签证。

He thought (that) they would give him 3 visa. 他本想他们会给他签证。

I expect (that) the plane will he diverted. 我料想飞机会改变航线。

I expected (that) the plane would be diverted. 我本料想飞机会改变航线。

在某些动词 (如answer, imply) 之后则一般需要用that。如：

He answered that he was from Austria. 他说他是奥地利人。

She answered that she preferred to eat alone. 她回答说她愿意独自吃。

I don’t wish to imply that you are wrong. 我无意暗示你错了。

The newspapers have implied that they are having an affair. 报纸报道暗指他们有染。

在较长的句子里，特别在“that从句”与动词隔开时，that一般不可省略。如：

The dealer told me how much he was prepared to pay for my car and that f could have the money without delay. 那个商人告诉我他准备出多少钱买我的汽车，并说我会立即收到款。