He_____ some German while he was away on a business trip in Berlin.
You can’t throw the waste everywhere. You should keep the classroom _________.
The more you _____ things to chance, the less chance there is for you.
After all, not even _____ speakers of English find it easy to do some reading aloud correctly in RP (Received Pronunciation).
If the boy had _____ the dog alone, it wouldn't have bitten him.
The gate is too ________ for a car to pass through..