to

当to作为动词不定式的标志时,后面加动词原形,作为介词的词性时,用v-ing的形式. 
这些动词后面接的to用动词原形： 
want, wish, hope, manage, pretend, decide, learn, agree, expect, demand, long, ask, care, choose, dare, fail, offer, plan, prepare, promise, refuse, desire, happen, appear, intend, would like to, be said to
to后用动名词：
be/get used to doing 养成做……习惯
get down to开始做……;look forward to…盼望……;stick to…坚持做……;lead to…导致……;devote oneself to…献身于……;to be devoted to …献身于……;pay attention to …注意……;object to 反对做……