difficult to deal withdifficult to rootdifficult to understanddifficult tripdifficultiesdifficultlydifficultydifficulty breathingdifficulty concentratingdifficulydiffidencediffidence regiondiffidentdiffidentlydiffidultydiffie hellman problemdiffracted wavediffractiondiffraction disc diffraction diskdiffraction gratingdiffraction modediffraction patterndiffraction ringsdiffraction spectrumdiffraction theorydiffraction tomographydiffraction wavediffraction zonediffractivediffractometerdiffractometrydiffusediffuse arraysdiffuse boundariesdiffuse bulgingdiffuse centromerediffuse complexdiffuse frontdiffuse illuminationdiffuse nebuladiffuse porousdiffuse radiationdiffuse reflectiondiffuse reflectordiffuse scatteringdiffuse seriesdiffuse sky lighdiffuse sky radiationdiffuse sounddiffuse spectrum
