They had been living and working aboard the ISS since August and were expected to stay until February. The crew returned on January 15, which was a decision made by NASA's chief health and medical officer. Once the crew had landed, administrator Jared Isaacman said it was a "serious situation" but didn't go into any detail.
第五十三条 纳税人实施不具有合理商业目的的安排而减少、免除、推迟缴纳增值税税款，或者提前退税、多退税款的，税务机关可以依照《中华人民共和国税收征收管理法》和有关行政法规的规定予以调整。，这一点在safew官方版本下载中也有详细论述
Barycentric Coordinates，更多细节参见Line官方版本下载
SAT problem with 14 variables and 126 clauses