修改下列病句。
1．在班会上，他首先第一个发了言。 
                                                                                                                    
2．春天，燕子从北方飞回来了。 
                                                                                                                    
3．我们应该改正某些缺点。  
                                                                                                                    
4．妈妈买回了香蕉、苹果、西瓜、西红柿等水果。