"lengthy and arduous" is a correct and commonly used phrase in written English.
It is typically used to describe a task, process, or journey that is both long and difficult. Example: The construction of the new highway was a lengthy and arduous process, involving years of planning and countless obstacles to overcome.
The process of getting on the show and formulating his pitch, he said, was lengthy and arduous — and very different from a standard pitch to venture capitalists.
Mr. Bloomberg may also have to begin the lengthy and arduous process of investigating state-of-the-art incinerators and finding places to put them.
Uppermost in the calculations as officials dispersed rewards was the need to ensure that the international coalition remained loyal to a campaign that could be lengthy and arduous for its members, particularly those with restive Islamic populations.
Commenting on his withdrawal, Hurt said: "I have recently been in hospital with an intestinal complaint and although I am much improved and on the road to a full recovery, my doctors have advised that it is too soon for me to undertake a lengthy and arduous stage role.
The settlement caps a lengthy and arduous negotiations process between the firm and the Securities and Exchange Commission and the New York Stock Exchange and makes Bear the last major Wall Street firm to pay fines in connection with improper fund trading practices first uncovered by Eliot Spitzer, the New York attorney general, in 2003.
Decolonisation is a lengthy and arduous process, that, according to Tiffin (1995: 95), may be defined as 'an ongoing dialectic between hegemonic centers systems and peripheral subversion of them'.
That student could do only one thing to effect change: she could attempt to amend the Michigan Constitution — a lengthy, expensive and arduous process — to repeal the consequences of Proposal 2".
But an applicant who wants the university to consider race as a factor has only one path available: to work to pass a new amendment that repeals the anti-affirmative-action amendment — which a federal appeals court called "a lengthy, expensive and arduous process".
The battle between this small fishing community and Shell's Nigerian subsidiary has been lengthy, arduous and imbalanced.
Because the accident took place deep in a lengthy tunnel, cleanup operations have been slow and arduous.
It would involve lengthy, arduous and potentially inconclusive constitutional negotiations with the provinces.
