JEAN: Where's Sally, Jack?
Where is/are ...在哪里？询问人或物的位置方位，
句中动词be的形式需根据主语的单复数(不可数名词)而定；
JACK:She's in the garden, Jean.
JACK :She's sitting under the tree
under prep.在..之下,表示一个物体在另一个物体的下面；
JEAN :Is Tim in the garden, too?
JACK:Yes, he is.
He's climbing the tree.
is climbing 现在进行时标志，表示现在正在做的事（be + 动词现在分词ing);
JEAN: I beg your pardon?
Who's climbing the tree?
JACK :Timis.
= Tim is climbing the tree.
JEAN : What about the dog?
为了避免重复原句中的主语和谓语动词，可以用What about这个结构，用来询问情况
JACK :The dog's in the garden, too
It's running across the grass
It's running after a cat.
