题目：It was essential that______（申请表在载止日期前寄回).
It was essential that______(申请表在载止日期前寄回).
喵查答案：the application form(should)be sent back before thethe application form(should)be sent back before the 句型It is vital/necessary/important/urgent/imperative /desirable/advisable/natural/essential+that中，从句用(should)+动词原形。