You should never_____to difficulties you meet in study

We had a really bad time about six months ago but now things are ____.

Do you know __________—I’m not sure. Maybe an English teacher

is expected to export 1 billion mobile phones this year, ________ by a surge in demand for smartphones worldwide

Whose book is this—It ________be Mary’s. J. K. Rowling is her favorite writer.—No, it ______ be hers . She never brings novels to school.