一般放在句子的开头
示例
A：He was very nervous and didn't dare to look up.
B：Obviously, he has a guilty conscience.
A：他很紧张，都不敢抬头。
B：很明显，他是心虚了。
A：Obviously, he passed the exam.
B：No wonder he is so happy.
A：很明显，他通过了考试。
B：难怪他这么开心。