What kind of musician do you like?—I like musicians _________write their own songs.
The following chapters provide step-by-step instructions for practical _______ of genetic (基因)engineering to agriculture.
He put salt into his tea __________mistake.[ ]
I hope we only have half an hour ____ homework, so we can have more time ___ our hobbies.
I usually get up _______ eight o’clock on weekends.[ ]