There was something wrong with the line. We couldn't ______ each other clearly.
A:listen
B:sound
C:hear
D:speak
《海国图志》的作者是林则徐,他提出了“师夷长技以制夷”的主张。
某思想家强调孝、悌、慈等伦理道德均源于人之自然本性,这位思想家是()