处理事故的“四不放过”原则是：事故原因没有查清不放过；事故责任者没有严肃处理不放过；

如图所示，已知n₁：n₂=4：3，R₂=100欧姆，变压器没有功率损耗．在原线圈加上交流电U₁=40V，则R₂上的发热功率是______．若R₃=25Ω时发热功率与R₂相同，则原线圈与副线圈的n₁：n₃=______．

制订职业接触限值属于哪一级别的预防工作（）

A.一级预防

B.二级预防

C.三级预防

D.初始预防

E.基础预防

医师执业活动中造成医疗责任事故的由县级以上卫生行政部门给予警告并责令（）

A.吊销执业证书

B.暂停6个月至1年执业活动

C.重新进行执业资格考试

D.批评教育

E.暂扣执业证书

On November 15, 2008, Grinell Construction Company decided to issue bonds to help finance the acquisition of new construction equipment. They issued bonds totaling $10000000 with a 6% coupon rate due June 15, 2028. Grinell has agreed to pay the entire amount borrowed in one lump sum payment at the maturity date. Grinell is not required to make any principal payments prior to maturity. What type of bond structure has Grinell issued（）

A. Serial bonds.

B. Bullet maturity.

C. Redeemable bonds.

探明情况只是指查清河势、工情和险情。