We need to d________ when we should start the project.
—I’m sorry to bring you so much ________ (麻烦). —It doesn’t matter.
There are many ________ (乘客) on this bus. Let’s wait for the next one.
Who can________ ________ (解出) this maths problem?
. He realized that his deskmate was ________ ________ ________ (看不见了).