在开始考试时，可以说以下几句话：

1. "The exam will begin shortly, so please take one last moment to review your notes."

2. "Please prepare yourself for the challenges ahead."

3. "Good luck, and may the best of your abilities shine through."

4. "Remember to stay calm and focused during the exam."

5. "You've prepared well, now go in and do your best."

这些句子可以帮助你在考试前调整心态，提醒自己做好准备，并以积极的态度面对考试。