看拼音,写词语。
bō làng
xiě zì
dēng guāng
píng guǒ
láo dòng
zuò chū huí dá
měi lì
____
函数f(x)=x+3x的零点所在的区间为( )
(Ⅰ)证明:AC⊥D1E;
(Ⅱ)求DE与平面AD1E所成角的正弦值;
(Ⅲ)在棱AD上是否存在一点P,使得BP∥平面AD1E?若存在,求DP的长;若不存在,说明理由.
____m/s,它在水中的速度比在空气中要____.
用所给单词填空
(1)Sometimes we ____ food at home. (2)I ____ drinking milk. (3)We often ____ CCTV news at 7:00 in the evening. (4)I ____ the Internet once a day.(5)The results for “read English books”____ fun.(6)How often do you ____ to the English corner? (7)Everyone will____ you if you need any help.(8)The sun ____ once a day. (9)Walking can ____ you in good health.(10)I____ nine hours every night.