Final answer:
The most effective strategy to help students recognize difficult words is to read the words aloud, construct them with plastic letters, and write them, as this multi-sensory approach reinforces word recognition.
Step-by-step explanation:
When assessing students' reading ability and noticing a struggle with words such as "enough," "sign," "night," "through," and "was," the instructional strategy that will have the greatest impact on building students' automatic recognition of such words would be incorporating an activity in which students read each word aloud, build each word with plastic letters, and write each word.
This multi-sensory approach addresses different learning styles and reinforces word recognition through auditory, visual, and kinesthetic methods. By engaging in these activities, students actively participate in their learning process, which promotes better memory retention and helps to facilitate the development of automaticity in reading.