I think...(..., I think.)

①I think....(事実fact)　I guess/I suppose/I imagine(事実ではないnot fact)
※I think等を文末につけると柔らかい印象を与える FROM NOVA fall 7
A: Any ideas what I should get for my nephew?
B: How old is he again?
A: Going on seven, I think.
B: What kinds of things is he into?
A: I'm not sure. Cars and spaceships, I imagine.
B: How about getting him a radio-controlled car?
②be going on+数字はある人がほぼその年令であることを言う around this age
A: He must be going on 70.　He is going on 40, I think.
B: I don't think she would be interested in a music player.
※wouldを使うことで推測、仮定している
She likes cats.(fact)/She'd like a cat.(imagining)
I don't think she is interested in a music player.
※普通文なのである程度言い切っている
B: He could do with a sweater, I suppose.
③could do with/can do withは何かを持つことによってプラスになるという意味で使う
※might need/might like
She could do with a new bag.
The one she's using now has a big hole in it.