根据句意，在答卷标有题号的横线上，写出括号内所给单词的适当形式。
The leather bag may be one of the ___________ (visit) over there.
It is said that this morning Beijing had the __________ (thick) fog this year.
My father will go to Beijing on business at the   ____          (begin) of next month.
Little Tommy didn’t come to school today because of his ___________(ill).