______side of the street is lied with different shops, ______of which sell electronic products.

No agreement was reached in the discussion as neither side would give way to ______.

 It is so difficult a problem that ____ student in this class ____ work it out.

Is _______ Qinghai-Tibet Railway plays an important role in China’s railway history the topic that you’re coming to?

I bought ______ for my son，but ______ for myself.