From Longman Dictionary of Contemporary EnglishI thinkI thinkPROBABLYused when you are saying that you believe something is true, although you are not sureMary is in the garden, I think.I don’t think Ray will mind.‘Do you understand what I mean?’ ‘Yes, I think so.’‘Haven’t we met before?’ ‘I don’t think so.’I thought he was honest, but I was wrong. →think
Examples from the Corpus
I think so• "Is Matt coming to the party?" "I think so."• But you were there. I thought so.• The foundations 243 think so, my friends think so, even I thought so.• Actually, I think so too.• Sound good? I thought so too.