A terrible thought Mr. Smith when he was leaving for work: what if an accident happened while his son was alone at home?
—I rang you at about nine, but there was no reply. —Oh, that was probably I was seeing the doctor.
She looks sad. Could you please tell me ____ that prevents her from being as happy as before?
I just can’t figure out the meaning of the word---so I’ll have to ___ the dictionary.
Being determined is a kind of quality and that’s ________ it takes to do anything properly.
Before making your speech, you’d better ________ your thoughts and ideas.