1/2软馈需要弯曲布放时,要求弯曲角保持圆滑,其二次弯曲的半径不超过()。
A.20mm
B.30mm
C.40mm
D.50mm
参考答案:C
Which of the following is not an institutional shareholder?()
A.banks
B.pension funds
C.insurance companies
D.individual shareholders
胚珠的合点是珠心、珠被、珠柄交汇之处。