用括号中所给单词的适当形式填空
You'dbetter_______somemedicine,oryou'llfellbad.(take)
Don'tforget________amessagetomenexttime.(leave)
Wecrowedroundtheplacetoseewhat________(happen)
They_________--themapofthecountrybrforetheyleft.(study)
麻烦还说一下为什么?