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1.
a. He was too weak to lift the box.
b. He was not strong enough to lift the box.
c. He was so weak that he could not lift the box.
d. He was such a weak boy that he could not lift the box.
2.
a. The room was too dirty to learn .
b. The room wasn't clean enough to learn .
c. The room was so dirty that nobody can learn it.
d. This was such a dirty room that nobody can learn it.