用方框中所给词的适当形式填空。

however,  speak,  express,  period,  pride

Words can't _______ how excited I am now.
The work must be finished in a one-month _______. 
—Our class won the Olympic Math contest.
—Congratulation! You must be _______ of it.
She said it was so, he made a mistake, ________. 
A guest _______ gave us a talk about environment last week.