They lost their way in the forest, and . Which of the following is wrong?
It’s foolish to go to the ___ of taking music lessons if you never practise.
He is delighted to have ___ the examination.
The carpet where he _____was warm and comfortable, so he slept soundly.
Any student _____ will be disqualified from the exam.
The theory he sticks to ______ to be of no use in our studies.