为了简化零件的形状和结构，便于锻造而增加的一部分金属，称为（）。
参考答案：余块
水利水电工程的永久性主要建筑物的级别，总共划分为（）级。
A.三
B.四
C.五
D.六
After staying in hospital for long, the patient was advised to go to the seaside so that his health
could _____ soon. [ ]
A. pick up
B. set up
C. make up
D. get up
