判断下列句子是简单句 并列复合句还是主从复合句
1 . We often study Chinese history on Friday afternoons
2 . Lose one hour in the morning and you will be looking for it for the rest of the day
3 . In some Western countries the demand for graduates from MBA courses has fallen
4 . The farm which I visited last year is a nice place
5 . When and where they should build a new power station is a difficult problem for them