A. cannot allow          

B.cannot be allowed

A. can turn

B. can be turned

A. will not be employed

B. will be employed

A. ought to be made

B.needn't be made

A. cannot buy

B. cannot be bought

A. will hold    

B. will be held

A. Can't this issue express

B. Can’t this issue be expressed

A. is observed     

B. must be observed

C. must have observed

D. had better observe

A. can be pick

B. can pick          

C. needn't pick

D. should be picked

A. should be typing

B. must be typed

C. needn't type

D. needn't be typed

A. need typing

B. needn't be typed        

C. need to type   

D. needn't typing

A. will cancel      

B. will be cancelling       

C. will be cancelled        

D. will have cancelled

A. needn't study

B. needn't be studying

C. needn't have studied

D. needn't have been studied

A. needn't be taken         

B. needn't be taking                    

C. needn't take

D. needn't taking

A. has to be wrapped                                      

B. has to wrap

C. had to be wrapped

D. had to wrap

A. must forget                                                        

B. must be forgotten

C. must have been forgotten                                 

D. must have forgotten

A. can be participated      

B. could be partipated    

C. can participate            

D. could participate

A. might be replaced          

B. might have been replaced

C. should have been replaced

D. should be replaced

A. must be worn    

B. must wear

C. must have worn              

D. must have been worn

A. is supposed to sign                 

B. is supposed to be signed

C. was supposed to sign

D. was supposed to be signed