1. Many teenagers feel _______, as if no one _______ them and the changes they are going _______. Day by day, everything seems different, yet the same.

2. Many boys become _______ — they want to find their own limits and the limits of the world around them, but may not have the _______ to make good choices in their _______.

3. The truth is, diet and _______ of life are often a problem for teenagers. However, the good news is that you can _______ better, look better and have more energy if you eat the _______ food and exercise _______.

主动脉瓣关闭不全，不可能出现的体征是

A．毛细血管搏动征

B．主动脉瓣第二心音亢进

C．主动脉瓣区可闻及叹气样舒张期杂音

D．枪击音和杜氏双重杂音

E．心浊音界呈靴形