Growing up _____ be difficult, for you will come across many things that confuse you.
He had to pause from time to time to wipe the sweat from his forehead, because the air-conditioning system ____.
Computers and mobile phones, though they are indeed making our life ____ and more ____, have reduced the need for face-to-face communications.
The woman ____there under the tree, ____ in a blue shirt, is our headmaster.
The new technology, if____ to farming, will help increase the grain output.
More and more high-rise buildings have been built in big cities____ space.