【wouldliketo/wantto1.Theyshouldbeallowedtopracticetheirhobbiesasmuchastheywant.2.Theywon'tallowhimtotrainasmuchashewouldliketo.3.Youcankeepquietifyouwantto.为什么2,3后面有to,而1没有?是否可以加上4.Healw】

　　wouldliketo/wantto

　　1.Theyshouldbeallowedtopracticetheirhobbiesasmuchastheywant.

　　2.Theywon'tallowhimtotrainasmuchashewouldliketo.

　　3.Youcankeepquietifyouwantto.

　　为什么2,3后面有to,而1没有?是否可以加上

　　4.Healwaysthinksmoreofhimselfthanofothers.

　　第二个of是否可以省略.

　　还有类似的and连接的to,为什么有的句子前后两个to,而有的后面省略了.