Malaysia Airline Flight MH370 seemed to have been _______to only a mystery after so long and hopeless a search.

Taobao is a popular online shopping website, ________ varieties of items at low prices.

Who is ____—–Alan.

The teacher requested that we _______ detailed notes in class because they are more ______ than our memory.

The question was _ by the teacher and only Tom _ to answer the difficult question.