三年级有56名同学参加了语文或数学竞赛，其中参加语文竞赛的有30名，参加数学竞赛的有35名，有多少名同学同时参加了这两种竞赛？
30+35-56=9（名）
Don’t take his remarks too seriously. He was so sad that I don’t think he really________ what he was saying.
A．knew
B．knows
C．besides
D．therefore
简述新斯的明的临床应用。
