We may find that learning a foreign language does not have to be ______learning our mother tongue, but can in fact be as easy.

untry has already sent up threeunmanned spacecraft , the most recent at the endof last March.

e arrived, she went straight to ___ kitchen andstarted to prepare ___ meal for us

The sign x ____ an unknown number. [ ]

Why do you choose to work in an international travel agency—Well，you know，English is my ________.So it is my best choice.