—I called you yesterday evening, but nobody answered the phone. --Oh, I ___ a walk with my parents at that time.
We will wait until everyone ________ back.
Wang Hui hopes ________ a scientist in the future.
—Where is Gary? —He _______ in the library.
Lily and Grace are my best friends. ________ of them are very smart.
—________ I use your pen? — Sure. Here you are.