Hi~Nayoon~ Maybe Korean counld be very complicated. The expressions you mentioned above have the same meaning. Good luck to you~

-는 듯하다 and -는 듯싶다 practically have the same meaning. 듯하다 is more plain sounding (factual) while 듯싶다 is softer and more personal, but the difference is very small. The others also have a similar meaning with a slight nuance difference. I tend to translate them as follows, but it's more a personal preference than any established theory. - -는 것 같다 = It seems that ... (것 = thing, fact, idea; 같다 = is similar to) - -는가 보다 = [subject] appears to ... (보다 = to see, look as an independent verb, or "it appears" as an auxiliary) - -는 모양이다 = It looks like ... (모양 = appearance, 모양이다 = it looks) Examples: - 날이 추워지는 듯하다 = ... 듯싶다 = 날이 추워지는가 보다 (evokes a sense of spontaneous perception). - 강아지가 아픈 것 같다 (more judgment/conjecture than with -는 듯하다, -는 듯싶다, -는가 보다) - 강아지가 아픈 모양이다 (모양이다 may be in between the two camps, somewhat closer to 것 같다)