Some of the students are not sure ___ spelling the word, while others are not sure ___ the use of some grammatical rules.
--- Are your family ready for rafting? ---Yes, I really want my children to experience that they are young.
Attention! _________ in the form right now, making sure that every detail supplied is accurate.
It is believed that high achievers are ambitious, hard working, and work toward personal standards of excellence _____ material rewards.
Many people like to talk about generation gaps. I don’t think there isin my family, though.
-- It's so cold! Why are your windows still open? --- Oh, they _______.