为了测试青霉素能否治愈和预防性病,美国研究人员竟然在1946年至1948年故意让1300多名危地马拉囚犯、精神病患者和性工作者染上淋病、梅毒和软性下疳等性病。这违背了
A. 科学性原则
B. 尊重原则
C. 公正原则
D. 有利原则
找出下面句子中用一般过去时的句子：
A. There will be a football match on TV this evening.
B. A week ago, Kitty and Ben were in the countryside.
C. I was up before the sunrise one October morning.
D. Tom and Mary came to China last month.
找出下面句子中用一般过去时的句子：
A. She was sixteen years old at that time.
B. Did you have breakfast this morning?
C. I can still remember those potato planting days.
D. We had several gardens around our old house.
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