We use the construction 固然…但是… to gently express a disagreement or opposite point of view: “That's true, but…”.
We should state 固然 in the first part of the sentence right after the subject. In the second part, we firstly state the conjunction “but” 但是 , 可是 , 不过 and then say the fact that diminishes the importance of what was said in the first sentence.
Sometimes 但是 and 可是 may be shortened to 但 and 可 respectively.
If the sentence has two subjects, we state the first one before 固然 and the second after the conjunction “but” and before the second predicate.
He's certainly smart, but very lazy
tā gùrán cōngmíng, dàn fēicháng lǎn
This method is certainly effective, but it will not solve all problems
zhè ge bànfǎ gùrán yǒu xiàoguǒ, búguò bú huì jùjué suǒyǒu de wèntí
Doing more work is certainly good, but we are not robots