Selecting a phone for personal use is not easy, because the techonology ____so rapidly.
A. is changing B. has changed
请教专家老师,选择 A,而不选择 B 的理由?
科学技术是瞬息万变的,随时一直正在变。选 B,这个变化的动作已经完成了,那么Selecting a phone for personal use 就很 easy 了。