It is the idea____smiles can get rid of cold ____has been proved by the researchers many times.
It was not until near the end of the letter ______ she mentioned her own plan.
It was only after he had read the papersMr. Gross realized the task before him was extremely difficult to complete.
An awful accident, however, _____occur the other day.
It was probably at that moment _____ I understood what kindness really was.
—What was it that caused the party to be put off? —________ the invitations.