He studied very hard all the time because he didn’t want to ()in his studies.
A. fall behind
B. be left behind
C. left behind
D. Both A and B
This race was her last chance to win a place on the national team so everything was ()_.
A. dangerous
B. in stake
C. at stake
D. in charge
Johnny is a great dancer; he _()above the rest for his perfect performance.
A. stands by
B. stands for
C. stands out
D. makes for
If ()_, the bird flu would produce a powerful poison that would kill the patients.
A. not treat
B. not treated
C. untreated
D. Both B and C