English Senior High almost 10 yearsago

主語が単数形なら絶対動詞にsがつくのですか？

English Junior High over 10 yearsago

（are/the classes/know/long/don't/how/I） を並べ替えたら ❶I don't know how long the classes are. ❷I don't know are how long the classes. どっちかですか？？