考 Kǎo is 'consider' or 'take (an exam)':
Common words: 考虑 kǎolǜ 'to consider', 高考 gāokǎo 'university entrance exam'
烤 Kǎo is 'roast':
Common word: 北京烤鸭 Běijīng kǎoyā 'Peking duck'
Kǎo is 'torture':
Common word: 拷问 kǎowèn 'question via torture'
教 Jiāo is teach:
Note that the element bottom left is 'child' (子 zǐ).
It is read jiào in compound words.
Common word: 教育 jiàoyù 'education'