现在完成时的被动语态
观察上面对话, 并类比填空。
1. First as a PC and then as a laptop, I have been used(use) in offices and homes since the 1970s.
2. Since the 1970s many new applications have been found(find) for me.
3. I have even been put(put) into space rockets and sent(send) to explore the Moon and Mars.