—What are you busy with recently? —We have been looking into how the machine breakdown __________.
The young lady from Australia has a gift for creating an atmosphere for her students _________ allows them to communicate freely with each other.
I’m always ________ about what I say because careless remarks are likely to hurt others’ feelings.
Evidence has been found through years of study __________ children’s early sleeping problems are likely to continue when they grow up.
Two lawyers have donated $ 50, 000 to _________ our school’s campaign “Help the Needy”, which was started by our former headmaster 10 years ago.
Don’t touch your eyes, nose and mouth, because they aren’t covered by skin and can ________ the virus easily.