安全阀的开启压力（定压）为最高工作压力的（）倍。
A.0.9～1.0
B.1.05～1.10
C.1.0～1.1
D.1.1～1.2
参考答案：B
根据对话情景，填入恰当的单词。
A: Hi, Gina. Where are you going?
B: I'm going to a gift(礼品)shop.
A: Do you want to 1. __________ a gift?
B. Yes, I do. Linda's birthday is coming. And I want to give her a surprise.
A: Really? 2. __________ is her birthday?
B: It's on November 20. Are you 3. __________ that day?
A: Yes, I am.
B: Great! Can you go to the 4. __________ with me?
A: Sure, I'd love to.
硅铁冶炼操作中的“三个坚持”是坚持（），坚持（），坚持（）。
