explain

in detail

The teacher explained the math problem in detail so all the students could understand it.

fully

The teacher fully explained the new grammar rule so everyone could understand it clearly.

partly

The stress of moving partly explains why she felt so tired last week.

easily, readily

The teacher readily explained the difficult math problem to the confused students.

patiently

The teacher patiently explained the math problem until all the students understood it.

concisely, succinctly, tersely

The teacher explained succinctly how photosynthesis works so all the students could understand.

be able/unable to, can/could

The teacher asked why he hadn't finished his homework, but he couldn't explain his reasons.

purport to

This new diet claims to explain why people gain weight so quickly.

be difficult to, be hard to

Why the old computer broke down was hard to explain to my grandmother.

hasten to

He noticed her confused expression and hastened to explain the new company policy.

let sb

Let me explain how to use this new software before you start working on it.

about

The teacher spent time explaining about photosynthesis to help the students understand the process.

to

The teacher explained the difficult math problem to the class yesterday.

explain everything

The instruction manual explains everything you need to know about setting up your new printer.

go a long way/some way towards explaining sth

Their difficult childhood went a long way towards explaining their fear of commitment in relationships.