芦苇
It is agreed that a person is more likely to suffer from arteriosclerosis ______.
A.as he becomes older
B.if his immune system does not work properly
C.when the cells of his brain and spinal chord decline
D.when the cells in his kidneys decline in number
简述焊接冷裂纹裂纹产生的原因及防止措施。
铺展性
构树