提速道岔顶铁、限位器采用防松螺母。

我国原始热带雨林保存最为完整地区是( )

A．西双版纳

B．珠江三角洲

C．台湾南部

D．海南省

语法填空

     British people are allowing their manners to slip.It _1_ (claim) last week that more than eight out of

ten passengers refuse to give up    2   seats on the bus, train or tube.Around half of workers do not make

cups of tea   3   colleagues while 86% of people do not offer to help others carry bags.

      According to a survey, the main causes of decline in manners were lack of time and stress at work.

Jamie Wilson,    4   has worked as a health care provider for thirty years, said, "Spending just half an

hour a month helping someone else can make a real   5   (differ) to your life as well as theirs."

     "As a health care provider, we encourage our staff to get active in the community,   6   (support)

others.In fact, we give 100 days a year to staff to spend helping at   7   charity located in the city."

     "  8  all of us know that helping others is beneficial to them, many people don't realize that it can also

improve their own mental and physical health, "Dr Christian Jessen, a mental health expert, said."Simple

activities  9  walking the neighbour's dog or helping in the garden help to burn calories and improve

general   10   (fit), leading to a healthier and happier nation."

某施工单位承接某办公楼工程，总建筑面积19800m²，地上18层，地下 1层，基础为桩基筏式承台板，结构形式为现浇剪力墙结构，混凝土采用商品混凝土，强度等级有C25、C30级，钢筋采用HPB235级、HRB335级。

普通混凝土划分( )个等级，最高等级为( )。

A．12，C60

B．13，C80

C．14，C80

D．13，C60

使用手锯应注意的安全问题有哪些？

下列信息应在部海事局中文网站上公布（）

A、中文航行通告；

B、英文航行通告；

C、通过VHF发布的短期临时航行；

D、水上交通事故协查信息。