______ acupuncture developed, the simple “bian stones” were replaced first by stone and pottery needles, and ________ by metal needles.
The rise of oil prices made scientists search for new energy resources ______ oil.
You didn’t believe John won the first prize at the speech competition, ______?
I had reached a point in my career _____ I needed to decide which way to go.
Here are some new computer programs _____ for home buildings.
sweet and fresh, this kind of food is so popular with local people and the tourists.