根据语境,从方框中选择恰当的短语填空,有的需要变换形式。 grow up, be sure about, make sure, keep on, try one’s best 1. Mr. Smith ____________ working although he was tired. 2. Please give Mary a call to ____________ that she will arrive on time. 3. —Can you finish the work by yourself, Dale? —Yes, I ____________ it. 4. When we ____________, our parents will grow old. 5. Don’t worry. We will ____________ to find out the truth.