use int if you have a small number of classes,
赵先生 [email protected]，这一点在Line官方版本下载中也有详细论述
纳税人放弃退（免）税或者免征增值税的出口业务，在36个月内不得再次适用退（免）税或者免征增值税。。51吃瓜对此有专业解读
"It's an opportunity to … actually have the suits in microgravity, even if we don't go outside the vehicle in them. You get a lot of good learning from that," Isaacman said.