独立不定詞

to be frank with you, to be honest

that is to say

to tell the truth

needless to say

to be sure

strange to say

to make a long story short, to be brief

to be precise, to be more precise

to say the least, to be modest

to say nothing of A, no to speak of A, no to mention A

to begin with

to do one's justice

to make matter worse

not to say A