把下列句子改写为“把”字句和“被”字句。   
1．白茫茫的大雪笼罩着山川、田野、村庄。
                                                                                                                                                         
                                                                                                                                                          
2．他送受伤的小鸟回家。
                                                                                                                                                      
                                                                                                                                                      
3．老班长吃了草根和鱼骨头。 
                                                                                                                                                      
                                                                                                                                                      
4．洪水吞没了小伙子。