Well done! It is unfortunate that students don't just contact their teachers when struggling. :(
Answer:
Reprehensible - Blameless
Plausible - Unbelievable
Acumen - Inability
=>
They are crying because they need the sand to be moved for them
Good practices:
Speaking clearly
Standing straight and tall
Controlling your pacing
Speaking with the same volume
Moving your hand often to keep attention
Bad practices:
Looking at your notes the entire time