根据句意及所给的中文，写出恰当单词，使句子的意思完整、正确。
Red and Black are a good ________．(搭配）
You should choose your hobby ________ to the time you have．(根据)
There is no ______ that you’ll be successful in the future．(怀疑)
She is ______ with herself in her study．(严厉的)
Some people decided to donate their bodies for medical ________ after the death．(研究)