用CO2气体保焊()
A.可减少焊件氧化
B.可减少气孔
C.可减少飞溅
D.可减少空气中氮的有害作用
参考答案:A
阅读短文,判断正(√)误(×)。
We have a new classroom. It's so big and nice. We have a new teacher. She is beautiful (漂亮的). We have
eight new lights and I have a new desk. It's near the window.
( ) 1. We have a new classmate.
( ) 2. We have a beautiful teacher.
( ) 3. We have 6 lights.
( ) 4. My desk is near the door.
( ) 5. I have a new desk.
关于“疣状胃炎”的描述,错误的是()
A.圆形、椭圆形隆起性病变
B.形态规则,境界清楚
C.胃小区大小、结构正常
D.胃壁柔软
E.多数病灶小于1cm