The phrase "are two major difficulties" is correct and usable in written English.
It can be used when discussing or identifying significant challenges or obstacles in a particular context.
Example: "In this project, there are two major difficulties that we need to address: budget constraints and time limitations."
Alternatives: "present two significant challenges" or "involve two key obstacles."
In my view, there are two major difficulties with drawing direct causal links between media images and forms of social behaviour.
There are two major difficulties facing a view of this sort.
There are two major difficulties for researchers trying to clarify the presence or absence of sensitization: a) The gold standard is the quantitative sensory testing (QST) protocol [2].
"There are two major difficulties Bitcoin exchange customers have traditionally faced: banking troubles for the underlying exchange, and security of their coins," he said.
There are two major difficulties in learning from multiple side views for graph classification, as follows: Graph data naturally compose the primary view for graph mining problems, from which we want to select discriminative subgraph patterns for graph classification.
When f depends nonlinearly on z, there are two major difficulties (see (Yong 2010)) one meets: (i) What is the second-order variational equation for the BSDE (3)? it is not similar to the one in (Peng 1990).
There have been two major difficulties that hinder the use of a loudspeaker pipe system as a short-duration acoustic point source generator.
There are four major difficulty settings, but once selected you can go back and change any specific setting later.
There are two major reasons for the difficulty of detecting such particles.
However, there exist two major difficulties, especially when the size of image collections is too large (tens or hundreds of thousands).
I posit that there are two major stumbling blocks: 1) the difficulty of simplifying complexities between services so that statutory planning processes can incorporate the approach, and 2) the lack of cross-landscape assessment methods and examples.
