I often have conversations with John over_____ telephone, while keep in touch with Tom by_____ letter. A∕ , the B∕ , a C the, ∕ D the, a
No one has yet succeeded in solving the _____ of how life first began.
Can you tell me ______?
—She looks very happy. She ______ have passed the exam. --I guess so. It’s not difficult after all.
Mary,along with her parents,______to Paris.
The students were studying in classroom when, all of sudden,the lights went out.