Which of the following is not a principle of plant

Statements:Some combs are boxes.

All boxes are mirrors.

Conclusions:I. Some boxes are combs. 

II. Some mirrors are combs.

Statements: 

Only a few Pen are Pencils.

No Pencil is Rubber.

Only a few Pencils are Sharpner.

Statement:

I) No exam is tough

II) All tough are test

III) Some test are easy

IV) All easy are study

Statements:

All Swabs are Handles.

Only a few Handles are Sticks.

All Sticks are Containers.

Conclusions:

I. Some Swabs are Sticks

II. No Swab is a Stick

Statements:

Some tasks are work.

All work are job.

Some job are tough

Conclusion:

I. Some tasks are tough.