“正如”用英语单词 "as" 表示，它可以用作连词或副词，引导定语从句、状语从句或名词性从句，具体含义和用法如下：

引导定语从句

"as" 可以引导定语从句，指代前面提到的某个情况或事实。例如：

"I did exactly as she asked."

"His achievements are as good as his brother's."

引导非限制性定语从句

"as" 也可以引导非限制性定语从句，对主句的内容进行补充说明。例如：

"As we all know, America is a country with a short history."

"As is often the case, he stays up late."

引导状语从句

"as" 还可以引导方式状语从句、时间状语从句、原因状语从句和让步状语从句。例如：

"She sings as beautifully as her sister."

"As it was getting late, we decided to go home."

"As it was raining, we stayed at home."

"Although he was tired, he kept working."

引导名词性从句

"as" 可以引导名词性从句，如主语从句、宾语从句或表语从句。例如：

"As is known to us, he is a great scientist."

"She said as much."

根据上述用法，可以造句如下：

1. 正如我以前所说的，我一直都很努力。

2. 他就像一只饥饿的狮子一样猛扑猎物。

3. 正如报纸上报道的，那场事故造成了严重的后果。

4. 她说话的方式正如我所期望的那样温和。

希望这些例句能帮助你更好地理解 "as" 作为 "正如" 的用法。