The factory was fined for______ chemicals into the river.

The boy waved his hands to his mother, who was standing at the school gate, to ………….. her attention.

The construction work was carried out by the local contractor.

The opposition will be elected into government at the next election, without a ________ of a doubt.

The society was set up to______ endangered species from extinction.

The construction work was carried out by the local contractor.

The criminal was sentenced to death because of ____ of his crime.

The boy waved his hands to his mother, who was standing at the school gate, to ___________ her attention.

Thể tích của khối chóp có đáy là tam giác $A B C$vuông, $A B = A C = a$ và chiều cao $a \sqrt{2}$ là