—See the gathering clouds outside? Please take this umbrella with you.— .
_________ is known to us all that the earth is smaller than the sun.
Unreasonable ________, it turned out to be effective.
Due to bad weather we have to put ___ off until next week to go camping in the mountains.
—Do you know how to start the machine? —________.I’m a green hand.
We are a team so we must assist one another _____ completing the task.