英语语法的问题

Question

请问they choose purpose over happiness——have a clear sense of purpose even reduces the risk of alzheimer disease。请问这个句子中为什么have没变ing形式，并且为什么还做了主语，难道动词原形加名词可以做主语吗 麻烦各位大神告知

Answer 1

我是这么理解的，have前面是个破折号，也就是句子没完，说明have继续承接前句的主语they，也就是说they have a clear sense of purpose。
然后reduces的主语是前面的整个句子，可以理解为（That）they have clear sense of purpose reduces......
如果是动名词做主语，having a clear sense...，就不需要破折号了

Answer 2

这就是中英文之间的不同。在中文里，副词修饰动词总是放在动词前。如：意外地发现；飞快地跑；仔细地观察等。而英文则都是放在动词的后面。如：run fast ; watch carefully; find by chance...

Answer 3

Passage One
Questions 46 to 50 are based on the following passage.

The phrase almost completes itself: midlife crisis. It's the stage in the middle of the journey when people feel youth vanishing, their prospects narrowing and death approaching.

There's only one problem with the cliche（套话）. It isn't true.

"In fact, there is almost no hard evidence for midlife crisis other than a few small pilot studies conducted decades ago," Barbara Hagerty writes in her new book, Life Reimagined. The bulk of the research shows that there may be a pause, or a shifting of gears in the 40s or 50s, but this shift "can be exciting, rather than terrifying. "

Barbara Hagerty looks at some of the features of people who turn midlife into a rebirth. They break routines, because "autopilot is death." They choose purpose over happiness—having a clear sense of purpose even reduces the risk of Alzheimer's disease. They give priority to relationships, as careers often recede （逐渐淡化）.