first‧ly S3 / fɜstli $ -ɜr- / 副词 [句子副词]

used to say that the fact or reason that you are going to mention is the first one and will be followed by others → finally , lastly 反义词 lastly :

Firstly, I would like to thank everyone who has contributed to this success.

THESAURUS

first/firstly used when mentioning the first in a list of reasons, arguments, or questions to consider : I want you to consider these three points in your essay: first, what is the writer’s attitude to the war in this poem … | There are several reasons for this conclusion. Firstly …

first of all used especially to emphasize that the first of several things you are going to say is the most important thing : The content of the article must, first of all, be accurate. | First of all, a huge thank you to everyone who has supported us over the last two years.

in the first place spoken ( also for a start British English ) spoken used when giving the first and most important reason or example, especially when you are arguing or discussing something with someone : Our main priority should be better public transport – in the first place to reduce the amount of traffic on our roads. | He’s not the right person for the job. For a start he’s too young.

to begin with/to start with spoken used when telling someone the first and most important thing that you want to say : There are numerous activities on offer. To start with there are over 60 miles of walks with splendid views. | Let me tell you something about him. To begin with, he is the most difficult man that I know.