题目内容：

there are losts of english books here ,and ( )of them is easy to understand Aboth B ALL C evere D
each(解析

优质解答

and ( )of them is easy 谓语动词是is ,单数
both,意思为两个,前面说的是lots of没说两个,显然牛头不对马嘴
all,全部,对应系动词应该为are
every,每一个,没有every of的说法
each,每一个,each of 是短语,句子前后也连贯