最常见的两种癌胚胎抗原是________和_______。
参考答案：AFP；CEA
找出下列句子中错误的选项，将其序号填入题前括号里。
( ) 1. You farm is beautiful.
A B C D
( ) 2. Are those cow ?
( ) 3. I have some potatos and carrots.
( ) 4. How many sheep is there?
起升机构中采用的钢丝绳一般为（）钢丝绳。
A.交互捻
B.同向捻
C.混合捻
