The little boy won’t go to sleep ________ his mother tells him a bedtime story.
It is the protection for the trees _______ really matters, rather than how many trees are planted.
It is _______ he often fails in exams ______ makes his parents worried about him.
Who are making so much noise in the garden? —_______ the children.
It was lack of money, not of effort, _____ defeated their plan.
It’s more than half a century _____ my grandfather joined the Party and became a servant to the people.