helped后加原形还是过去式help后加原形.但如果句子中是过去式helped是加原形还是过去式?初中阶段所学介词有哪些?

helped后加原形还是过去式help后加原形.但如果句子中是过去式helped是加原形还是过去式?初中阶段所学介词有哪些? understand后加to 动词原形还是动词过去式,还是直接加动词ing. was后加过去式吗?did后加原形吗? thanks for后加原形还是ing plan后加动词原形还是ing? will后加动词复数还是原形? could后用原形还是过去式?那三单呢? he was lost and I helped him find his father为什么helped是过去式,而find是原形he wanted to play basketball yesterday为什么play不加ed一个动词是过去式、为什么后一个动词是原形存在 一个句子中，一个动词是过 often后加ing还是加s还是动词原形? 过去式后面加过去时还是原形. used to 后加动名词还是动词原形 feel 后加动词原形还是ing形式? the more...the more...后加形容词原形还是比较级 不可数名词后接动词原形还是加s? why not 后加动词原形还是V.ING? 动词SEE后加动词原形还是动词ING? follow/suggest/fllowl后加动词原形还是? and后的动词用原形还是加ing?