切削液可以增大切削过程中的磨擦,显著提高表面质量和刀具耐用度。
参考答案:错
用and或but填空
1. They play basketball_________ volleyball every day.
2. I like comedies_________ I don't like thrillers.
3. Jim wants to go to a movie_________ I want to play computer games.
4. Maria has a soccer ball_________ two basketballs.
5. I like playing with chickens_________ I don't like eating chic ken.
关于胎盘中绒毛间隙的叙述,哪项是错误的
A.游离绒毛浸浴于母血之中B.母体的螺旋动脉开口于绒毛间隙C.绒毛干之间或绒毛与基蜕膜间为绒毛间隙D.胎儿的血液在间隙内与母体血相混合进行物质交换E.绒毛间隙内充满母体血液