根据括号内所给中文写出正确的单词。

1. All my classmates in this school are very _____. (有礼貌的)

2. We have a computer lesson on _____ morning. (星期四)

3. The tall boy over there is good at _____. (游泳)

4. Do you often have dinner at your _____ home at the weekend? (祖父母)

5. There are _____ boys in my class. (二十)

对某种产品的6件不同正品和4件不同次品一一进行测试，直到区分出所有次品为止，若所有次品恰好在第五次测试被全部发现，则这样的测试方法有______种（用数字作答）