A:glancing at
B:watching at
C:glaring at
D:staring at
如图,一张方桌可以坐4人,两张方桌拼起来可以坐6人,三张方桌拼起来可以坐8人…像这样n张方桌拼起来可以坐____人,坐68人需要____张方桌.