根据句意，写出括号内所给单词的适当形式。
After discussing for two hours, one of the most important ____________ (decide) was made.
We ____________ (simple) couldn’t wait for the first lesson given by Dong Qing.
Susan is an even ____________ (lively) girl loved by everyone.
We got excited when we ____________ (success) in working out the difficult problem.