However, at times this balance in nature is disturbed, ____ a number of possibly unforeseen effects.

With the popularity of network, email has largely ________ the traditional letter.

I am out of breath. I can’t go any further.—__________. I am sure you can make it.

I was at the cinema at nine o’clock yesterday evening. What about you—I _______ TV at home.

_______ that they may eventually reduce the amount of labour needed on construction sites by 90 percent.[ ]