如图所示为生活中常用的热水瓶，其外壁采用镀银的双层玻璃，并将中间抽成真空，这是为了减少 _______ ．注入一定量的热水后，立即盖上软木塞，软木塞会跳起来．这一过程中瓶内气体的 _______ 能转化为软木塞的机械能．汽油机的 _______ 冲程也发生同样的能量转化．

Which of the following signs and symptoms is classic for a patient with rheumatoid arthritis()

A. Joint swelling, joint stiffness in the morning, and bilateral joint involvement.

B. Crepitus, development of Heberden’s nodes, and anemia.

C. Pain on weight-bearing, rash, and low-grade fever.

D. Fatigue, leukopenia, and joint pain.