The twin brothers stand under the tree, ______ and say nothing.
How much bread is there? -_____________.
Only when it is hungry ______ a human being.
Only _______ as an interpreter _______ how important it is to grasp English.
The physics teacher once said that we first _____the lightning followed by thunders because light ______ faster than sound.
You'd better _______ your score and see if you have passed the exam.