题目

下列各项关于调查方法的描述，不正确的是（） A . 调查时要将所有对象都逐一调查 B . 调查时首先要明确调查的目的和对象 C . 森林资源的定期清查、人口普查都是常见的调查 D . 调查过程要如实记录，并仔细整理分析结果，有时还需要进行统计 答案：A He _______ the letter typed, but he decided to handwrite it and send it in person in order to show his sincerity. A. must have had          B. should have had C. would have               D. could have had