Science and technology are developing ______ quickly that some new electronic products are out-of-date within several months.

He is the only student______ I’ve ever met ______ could answer this question .

Amy is _______ unusual girl. She has traveled to 15 countries in _______ world.

Liu Huan is a great singer ________ long hair. [ ]

I________astudentandMissLiu________myteacher.