Would you please keep silent? The weather report ________ and I want to listen.
A:is broadcasted
B:is being broadcasted
C:has been broadcasted
D:had been broadcast
①一食或尽粟一石____
②虽有千里之能____
③其真无马耶____
④且欲与常马等不可得____
(Ⅰ)求证:平面PAD⊥平面ABCD;
(Ⅱ)设Q是棱PC上的点,当PA∥平面BDQ时,求二面角A﹣BD﹣Q的余弦值.
下面每句话中有一个错别字,请找出并加以改正。①奇怪的是,王老师说这番话时,竟第一次严肃得面无一丝笑容,一时间满教室鸦鹊无声。②水藻真绿,把终年伫蓄的绿色全拿出来了。③既使她写字的时候,我们也默默地看着她。④牛背上牧童的短笛,这时候也成天瞭亮地响着。
设a=49984999,b=66656666,c=99979999,那么____ >____ >____ .