it was 空格he fell ill suddenly that he didn't come to the meeting this morning.
问题描述：
it was 空格he fell ill suddenly that he didn't come to the meeting this morning.
a:because b:since c;as; 为什么?
答
用because,强调原因中的特定用法,since与as表原因一半只用于句首或单独成短句.