Read the following sentence. alayna has been playing with those blocks all day. what is the verb tense, and what is the meaning of the verb tense?
a. present progressive expresses something that is happening right now.
b. present perfect progressive expresses something happened in the past and is still happening.
c. present expresses something that is happening in general.
d. present perfect expresses that an action happened at an unspecified time before now.