用所给词语的正确形式填空..
Just when I opened the door,a little boy _______（appear) in the corner.
The number of the students in our class _______(be) forty.
Make sure _______(not forget) to make your umbrella with you .
As a student ,your job is _______(work) hard .
Nothing ________(find) in the bag yesterday.
The musician will _____ ______ ______ _____ _____(进行世界巡演）next year.