Word parts

teacher: teach + -er

teach + er forms teacher. The suffix names the person who teaches.
a person whose work is helping others learn
Ask the teacher after class.

owner: own + -er

own + er forms owner: the person who owns something.
The person a business or thing belongs to.
After two weeks the owner knew my order.

manager: manage + -er

Drop the final e of manage before adding er: manager.
A person responsible for a team or part of a business.
I sent it to my manager, Anne.

development: develop + -ment

develop + ment forms the noun development.
the process of growing, changing or becoming more advanced
Professional development is part of the job.

government: govern + -ment

govern + ment forms government. Here the noun names the governing institution.
the group of people responsible for running a country
The government published the transport plan.

agreement: agree + -ment

Keep the final e in agree before ment: agreement.
a shared decision or arrangement
We reached an agreement on the final price.

advertisement: advertise + -ment

Keep the final e in advertise before ment: advertisement.
a public message promoting something
The advertisement gives the shop's opening hours.

quickly: quick + -ly

quick + ly forms quickly, an adverb that can describe how an action happens.
Fast; without taking much time.
When my mother cooks fish, he comes quickly.

smoothly: smooth + -ly

smooth + ly forms smoothly. In the source example, it describes how the process happens.
Easily, without pauses or problems.
I answered them smoothly, perhaps too smoothly.

comfortable: comfort + -able

comfort + able forms comfortable. Learn its actual meaning with the example; a suffix alone cannot predict every word's meaning.
pleasant to use, wear or be in
These shoes are comfortable enough for travel.

dangerous: danger + -ous

danger + ous forms dangerous: having the quality of danger or risk.
likely to cause harm
It is dangerous to drive when you are very tired.

beautiful: beauty + -ful

Change the y of beauty to i before adding ful: beautiful has one final l.
very pleasing to see or hear
The old bridge is beautiful at night.

international: inter- + national

Put inter- before national: international. In this word, inter- relates nations to one another.
involving more than one country
She works with an international team.

subtitles: sub- + titles

Put sub- before titles: subtitles. The word names text displayed with a film or show, often below the picture.
Written words on a screen that show what people are saying.
I watch films with English subtitles.

biology: bio + -logy

bio- relates to life; -logy names a field of study. Together, biology names the study of living things; bio- is bound in this construction.
the scientific study of living things
The biology course includes the study of plants.

photosynthesis: photo- + synthesis

Put photo- before synthesis: photosynthesis. Photo- relates to light; use the full definition to understand the biological process.
the process by which plants and some other organisms use light to make food
Plants use light during photosynthesis.

Word-part references: Cambridge prefix guide, bio- and photo-. Examples and explanations here are original.