下图为“某大陆海岸变迁示意图”,图示地区引起海岸线变迁的主要外力作用是
A.地壳抬升
B.流水沉积
C.风力侵蚀
D.海浪侵蚀
答案:B
--- Do you know who designed the CD-ROM Around the World in Eight Hours?
--- Yes. It ______ by Nancy Jackson.
A.has designed
B.designed
C.designs
D.was designed
计算机的许多部件是由()来相互通信协同工作。
A、程序
B、命令
C、控制线
D、总线