根据中文提示写出单词，完成句子，每空一词。

小题1:__________, (不幸的是)we didn’t catch the school bus and had to walk to school.

小题2:Whatever your _________(选择) is, I will just follow you.

小题3:The books should be returned no _________ (迟) than next Friday.

小题4:He’d like to buy a present for his grandpa’s ___________(99) birthday.

小题5:Please be careful with these _________ (小刀). They are very sharp.

Y101型原棉杂质分析机分析时，流线板边口挂纤维，其产生的主要原因是（）

A、喂棉过多

B、流线板边口有毛刺或生锈

C、流线板和刺辊间隔距过小

D、流线板和刺辊间隔距过大