The to-infinitive and bare infinitive

I think John and Mary _______________ a quarrel yesterday.

• might be

• may have

• may have had

• might been

I didn't get all the facts, but they seemed _______________ about going to the cinema with Linda or something.

• to argue

• argued

• argue

• to have argued

I'd like _______________ Mary what it was all about, but I don't want _______________ as if I am poking my nose into their business.

• ask, sound

• asking, to sound

• to ask, to sound

• to ask, sound

You'd better _______________ out of it.

• stay

• stayed

• staying

• to stay

Let them _______________ out their problems themselves.

• sort

• to sort

• sorting

I didn't expect _______________ them there. Plus I didn't know they were dating.

• see

• to see

• saw

• seeing

I think you'd better _______________ your own business!

• minding

• to mind

• mind

I'm just curious _______________ when they started _______________ out together.

• knowing, to go

• to know, to go

• know, to go

• knowing, go

You should _______________ on something else, like science or art.

• focus

• focuses

• focusing

• to focus

I would _______________ less time gossiping and more time studying!

• spend

• spending

• to spend

• spent