单选题 At that time, we did not fully grasp the significance of what had happened.
【正确答案】 C
【答案解析】[解析] grasp“抓住，掌握，领会”，四个选项：give“给，授予”；attach“缚上，系上，贴上”；understand“了解，以为”；lose“遗失，错过，使迷路”。