BY
in the vicinity of - yn ymyl (no treiglad required)
Mae ei swyddfa yn ymyl gorsaf reilffordd.
His office is by a railway station.
near - ger (no treiglad required)
Roedd y ceffyl yn sefyll ger mynedfa i'r cae.
The horse was standing by the entrance to the field.
alongside - wrth + treglad meddal
Roedd y bagiau wrth gar y tu allan i'r gwesty.
The bags were by a car outside the hotel.
written by - gan + treglad meddal
Mae'r straeon gan lowyr a oedd yn gweithio yn y pwll.
The stories are by miners who were working in the pit.
by means of - drwy + treglad meddal
Roedd y felin ei phweru drwy ddŵr o nant.
The mill was powered by water from a stream.
by a time - erbyn (no treiglad required)
Bydd y siop ar gau erbyn pump o'r gloch.
The shop will be closed by five o'clock.
by transport - ar + treglad meddal
Mae'r rhan fwyaf o fyfyrwyr yn mynd i'r coleg ar fws.
Most students go to the college by bus.
TO
to a place - i + treglad meddal
Rydw i'n mynd i Gaerdydd yfory.
I am going to Cardiff tomorrow.
to a person - at + treglad meddal
Rhaid i chi riportio'r ddamwain at reolwr.
You must report the accident to a manager.
in order to - i + treglad meddal
Aethon ni i'r farchnad i brynu ffrwythau.
We went to the market to buy fruit.
as far as - at + treglad meddal
Mae'r trên yn mynd at Ferthyr Tudful.
The train goes to Merthyr Tydfil.
towards - at + treglad meddal
Dechreuodd yr orymdaith gerdded at ganol y dref.
The procession began walking to the town centre.
ABOUT
approximately - tua + treiglad llaes
Mae tua phedair milltir i'r pentref.
It is about four miles to the village.
around - o amgylch or o gwmpas (no treiglad required)
Roedd coed wedi'u gwasgaru o amgylch y parc.
There were trees scattered about the park.
concerning - am + treglad meddal
Derbyniodd yr heddlu adroddiad am bobl yn achosi difrod.
The police received a report about people causing damage.
on the point of - ar + treglad meddal
Roedd y grŵp ar gychwyn ar eu taith.
The group were about to begin their journey.
WITH
with a person - gyda + treiglad llaes
Mae'n gweithio gyda chydweithiwr.
He is working with a colleague.
with a tool or instrument - â + treiglad llaes
Seiniwyd y larwm â thrymped.
The alarm was sounded with a trumpet.
containing - â + treiglad llaes
Hoffech chi frechdan â chaws?
Would you like a sandwich with cheese?