岑参《白雪歌送武判官归京》中写沙漠冰封，愁云惨淡的景象烘托内心感受：担心朋友归京前路难行，牵动自己的思乡之情的诗句是：____，____。
I don't know if Tom _________ here tomorrow. If he ________, I'll tell you.
默写填空。
