I am trying to remember whether the sentences below are correct:
- I don’t know this guy being able to complete this task.
- I don’t know this guy can complete this task.
I think the first one is correct. (I know they don’t mean much but I am asking in grammatical manner.)
I am also trying to remember how to reduce the “who” within the following sentences:
- I don’t know this guy who has been doing this all along.
- I don’t know this guy who has done this all along.
Neither of the first two is correct. It should be
I don’t know if (or whether) this guy can complete this task.
“this guy can complete this task” needs a subordinating conjunction to be added onto the sentence “I don’t know” as a dependent (or subordinate) clause.