A、Since this is an especially important problem, let us concerntrate a bit and discuss it more deeply.
B、We sincerely hope that all present here will feel free to express your ideas and exchange various opinions.
C、Mr. Smith, I’m afraid we can’t hear you. Would you please speak louder or make use of one of the microphones in the center of the lecture hall?
D、So far we have discussed the following three points: one…; two …; and three …. Can we concentrate on these three points?
喵查答案：Since this is an especially important problem, let us concerntrate a bit and discuss it more deeply.
So far we have discussed the following three points: one…; two …; and three …. Can we concentrate on these three points?
