Weather experts advise us out if PM2.5 levels are above 500.
She ____ have left school, for her bike is still here.
They are ____ different sizes, shapes and materials, but they are exactly the same _____.
When you are older you can watch _____ program you like.
____ you eat the correct foods ____ be able to keep fit and stay healthy.
According to our school rules, no student ____ be permitted to carry mobile phones in class.