He will be watching her anxiously__she swims the long distance to England.为何不可以填during

during 是介词,它后面要跟宾语,表示一段时间,而宾语从句要有引导词（that, what, whether, when, why ...),这里she swims the long distance to England 显然不是一个宾语从句.假如用during,这个句子要改成：He will...