No one knows when such a custom first _____.
I rang and got ______ to him and he said he had got ______ the examination.
The husband and wife did agree ______ each other _______ it.
She may have been caught in the heavy traffic, ____ she won’t arrive here by five o’clock.
He didn’t do well _____ Chinese. He had some trouble ______ it.
Can you ______ the difference ______ the two phrases?