Answer: B) Let your grammar lessons be learnt.
Explanation for this question is being written.
Answer: A) Let the old people be helped.
Answer: A) Let the wall be built.
Answer: A) Active
Answer: A) Let you all be heard!
Answer: A) You are forbidden to walk on the grass.
Answer: D) Let what has been told to you be done.
Answer: A) You are suggested to carry it home.
Answer: A) It helps the driver concentrate and ensures safety for everyone.
Answer: B) Let the task be finished.
Answer: B) Let not the poor be insulted.
Answer: B) Let the lights be turned off.
Answer: A) Let them be told to stay here.
Answer: A) ACTIVE VOICE.
Answer: A) Let your doctor be visited regularly.
Answer: A) ACTIVE
Answer: B) Let the needy be helped.
Answer: B) Use a calm, polite tone.
Answer: D) Let the tent be put up.
Answer: A) Passive
Answer: B) Let all the necessary test be done soon.
Answer: B) Before
Answer: B) Let+new object+be/not be+past participle.
Answer: C) Let the door be shut.
Answer: A) You are advised not to walk on the grass.
Answer: B) Let the window be shut.
Answer: C) The money was given to Jim.
Answer: A) Let this not be tried at home.
Answer: C) You are ordered not to tamper with electrical gadgets.
Answer: B) False
Answer: A) Be sure to attend the meeting.
Answer: A) Active voice.
Answer: A) The master switch must be set to OFF.
Answer: B) May success be found by you.
Answer: A) Let + object + be + pp.
Answer: D) The window should be opened.
Answer: B) Passive
Answer: B) I should not be disturbed while I am preparing my project report.
Answer: B) You are requested to call him/me at once.
Answer: B) Let your money be deposited in the bank.
Answer: C) Let the door be opened.
Answer: B) Milk is added if you like.
Answer: A) Let the windows be shut at once.
Answer: C) Let the class not be disturbed.
Answer: B) Wear your gloves; the tube is labeled.
Answer: B) Do not eat.-Food is not allowed.
Answer: A) Let your work be completed.
Answer: A) You are advised not to shout at him.
Answer: A) Let one month's leave be granted to her.
Answer: B) The battery must not be discarded.
Answer: B) B, don't let the pen be thrown up.
Answer: D) The invoices should be reviewed carefully.
Answer: D) Let this bird not be caught.
Answer: B) Should the classroom be cleaned by her?
Answer: D) Let the windows be opened.