The phrase 'too hard to understand' is correct and usable in written English.
You can use it to describe something that is difficult to comprehend. For example, "I tried to read the instructions, but the technical jargon was too hard to understand."
Everything is too hard to understand until it isn't.
I don't think it's too hard to understand.
"I can do the plus and the minus, but the division seems too hard to understand".
The western liberal response sometimes tries too hard to understand this and as Andy points out, shades into self-deception.
Some say the scheme is too hard to understand; others claim that savers are still too scarred by the recent bear market.Occasionally governments are more blunt.
It's an odd feeling to just realize something so obviously in front of you but masked by trying too hard to understand it.
But you didn't really have to look too hard to see she didn't genuinely understand emotions or relationships: she was just mimicking scripts and scenarios from TV". "The doctors failed time and time again to see through her coping strategies.
To Japanese, our haiku may sound too subjective and hard to understand.
This research focus on interactive simulation to improve the learning curve of vehicle dynamics topics as it has been shown that engineer students usually find math and physics too boring and hard to understand when they are unable to map a topic to a real life problem, therefore a most interactive approach seeks to catch student attention while providing a sandbox to experiment and learn.
A key concept described on page 4 and illustrated in Figure 1a of the interaction between alleles at multiple loci being "written" into a further single locus that is being inherited is too vague and hard to understand.
The instructions and items are listed in Tables 1 and 2. Table 1 ABS-10 instructions Instructions Think of a situation in which you found academic activities too difficult and too challenging, in that it was hard to understand or too much work.
