by appointment only

[English Learner]

English Language Proficiency Tests, Advanced Level

ESL/EFL Test #694 "Prepositional Phrases - At, By, For and To (5)", question 9

We operate ......... appointment only. We don't take any walk-ins at this clinic. So, I can try to fit you in this week sometime if you like.

(a) at
(b) for
(c) by
(d) to

English Language Proficiency Tests, Advanced Level

ESL/EFL Test #694 "Prepositional Phrases - At, By, For and To (5)", answer 9

We operate by appointment only. We don't take any walk-ins at this clinic. So, I can try to fit you in this week sometime if you like.

Correct answer: (c) by
_________________________

thank you for calling my attention on you.

[Mister Micawber]

Thank you for calling my attention to your problem.
_________________
Native English teacher at Mister Micawber's