下列四个句子：（1）这首歌调太高，我唱不上去；（2）引吭高歌；（3）她是唱高音的；（4）请勿高声喧哗．其中“高”字指音调的是（　　）

据统计，中国人每年在餐桌上浪费的粮食价值高达2 000亿元，被倒掉的食物相当于2亿多人一年的口粮。提倡节俭、反对浪费势在必行。为此，我们必须（  ）

①发挥教育对文化传承的决定作用　 ②努力践行社会主义荣辱观

③大力弘扬勤俭节约的传统美德　 ④自觉抵制腐朽文化的侵蚀

设M={a|a=x²﹣y²，x，y∈Z}，则对任意的整数n，形如4n，4n+1，4n+2，4n+3的数中，不是集合M中的元素是（   ）

完形填空
    My mother is a doctor.She is unable to get back home 1 every day.And she has to work on weekends sometimes.So it's hard for her to do all the 2 after work.
    As a member of the family，I think it's my duty to 3 some housework.4Mom always says she doesn't need any help，there are always things I can do.5 ， I can help do the dishes and set the table.I'm sure Mom loves me 6 to help her.
    What's more，I'm trying to be 7.I wash my own clothes，tidy up my bedroom and take care 8 my things.I'm old enough to do these things.And I can't9 on my parents forever.
    Always show your 10 to your mom for everything she does.I believe she will feel sweet.Try it now.

关于数据筛选，下列说法正确的是：（   ）