In the experiment the scientist kept a watchful eye________the developments and recorded every detail.
I’m sure you ___ the exams; but what will you do if you ___ them?
If you want to buy ___ , you will still go to store.
My grandmother used ___ an English teacher.
Miss Liu will teach ___ English nest month.
—Where can I see Tom?—I don’ know where he is. He hasn’t arrived ___ .