Question

It's necessary for us ________ them every day． [　　] A． walking B． to walk C． walks D． to walking

Answer 1

答案：B
解析：

It's necessary for sb．to do sth．意为“对某人来说干某事很有必要”。此处walk意为“溜”“牵着动物散步”，them指猫、狗等一些宠物。