现代社会保障时期是以160多年前社会保障开始形成（）为起点的。
参考答案：制度
请你用所给词的适当形式完成下列句子。
1. Here are some things they have learned from ______(scientist ) studies.
2. Sunglasses are used for _____ (keep) out the sun.
3. The students are ______ (confuse) about the ______ (confuse) problem.
4. I’m considering _____ (study) in Beijing or Shanghai.
5. I felt _______(embarrass) when everyone looked at me.
当今世界，各国之间激烈的竞争，归根到底是_________的竞争。[ ]
A、军事力量
B、文化
C、人才（教育）
D、自然资源
