写出反义词
普通—____ 茂密—____ 寒冷—____
—Hello, Jenny. I'm doing my homework. The sums are very ____.
—Let me see. The sums are easy. Let me help you.
在绕地球做匀速圆周运动的“天宮“二号太空舱内，下列哪个实验可以正常进行进行（ ）
