这里is是谓语动词,是系动词,后面是表语.
第一个动词是谓语动词,第二个是非谓语动词.非谓语动词除了不做谓语,别的成分都可以做.
有的是不定式to do、 有的是动词原形,有的是ing形式
want/ decide/ hope/ plan/ wish/ would like/ need to do
tell/ ask/ want/ would like / wish /allow sb.to do
enjoy/ finish/ practice / allow / mind doing
make / have/ let sb.do
help sb.do =help sb.to do
感官动词 watch/ see/ hear/ find 等 +sb.do / doing do 指整个过程,doing指在做
begin to do= begin doing
like to do like doing 意思相近
forget to do/ forgot doing remember to do/ remember doing stop to do/ stop doing意思不同,不定式to do表示事情没做,ing表示事情做过