—What’s he doing? —He’s _________ books.A.read B.reading C.reads
who's______(完整形式) A.who is B.whose is
do not______(缩写形式) A.do't B.don't
them______(主格) A.theyB.the
strawberry______(复数形式) A.strawberrysB.strawberries
father______(口语形式) A.mom B.dad