is no simple answer, ________ is often the case in science.

Who’s that boy reading in the garden Is it David—-It______be David. I saw him in the classroom just now.

I had _______ bad headache. Do you have _______ address of People’s Hospital— I’m sorry to hear that. Here is ________ address.

With so much________my mind,I couldn’t hear what they were quarreling over.[ ]

Not until _____ more, _____ able to improve the situation. [ ]