是must doing sth 还是to do sth?

是must doing sth 还是to do sth? Attentions must be paid to do sth还是doing sth 是must to do还是must doing 还是must do? 是mind to do sth还是mind doing sth? worry about 是doing sth还是to do sth 到底是learn to do sth还是learn doing sth 是 stand doing sth.还是stand to do sth 是finish to do sth还是finish doing sth 是busy doing sth.还是busy to do sth. 是finish doing sth.还是finish to do sth, why not后面是doing sth还是 to do sth 请问是decide to do sth 还是 decide doing sth? 是Let to do sth还是 Let doing sth? 是hard to do sth 还是 hard doing sth 是begin to do sth还是begin doing sth? 是learn to do sth 还是learn doing sth 快 must 后面是加to do sth.还是do sth. 是take sth.to do sth.还是take sth.to doing sth.