他正在寻找书，这可以用中文翻译为 "他正在找书"。
来源：
"寻找" 和 "找" 都是动词，表示正在进行的动作。它们的意思是 "to try to find something or someone by looking or searching for them"，即通过查找或搜索来寻找某物或某人。
英文例句：
He is looking for a book. (他正在找书。)
She is searching for her lost keys. (她正在寻找她丢失的钥匙。)
They are trying to find a solution to the problem. (他们正在尝试找到解决问题的方法。)
希望这些信息能帮助到你。
来源：
"寻找" 和 "找" 都是动词，表示正在进行的动作。它们的意思是 "to try to find something or someone by looking or searching for them"，即通过查找或搜索来寻找某物或某人。
英文例句：
He is looking for a book. (他正在找书。)
She is searching for her lost keys. (她正在寻找她丢失的钥匙。)
They are trying to find a solution to the problem. (他们正在尝试找到解决问题的方法。)
希望这些信息能帮助到你。