strenuous in czech strenuous in german strenuous in danish strenuous in spanish strenuous in french strenuous in italian strenuous in russian strenuous in swedish strenuous in albanian strenuous in belarusian strenuous in estonian strenuous in finnish strenuous in greek strenuous in croatian strenuous in hungarian strenuous in lithuanian strenuous in portuguese strenuous in romanian strenuous in slovak strenuous in ukrainian strenuous in polish