21) __________ is necessary for the development of strong bones and teeth.
(A) It is calcium
(B) That calcium
(C) Calcium
(D) Although calcium
22) The examiner made us __________ our identification in order to be admitted to the test center.
(A) showing
(B) show
(C) showed
(D) to show
23) This legend has been _________ from father to son.
(A) handed down
(B) handed for
(C) handed in
(D) handed over
24) By the twenty-first century, the computer ________ a necessity in every home.
(A) 3081 feet
(B) 3181 feet
(C) 3281 feet
(D) 3381 feet
25) _________ at 212 degrees F and freezes at 32 degrees F.
(A) Waters boils
(B) The water boils
(C) Water boils
(D) Water boil
26) The bacteria in milk is destroyed when ________ to at least 62°C.
(A) it be heated
(B) it heated
(C) it is heated
(D) it will be heated
27) We were ________ by the result.
(A) surprise
(B) surprised
(C) surprising
(D) to surprise of
28) The laboratory has a _________ of equipment.
(A) large amount
(B) large number
(C) little amount
(D) big amount
29) The general public ________ a large number of computers now, because prices are beginning to decrease.
(A) must buy
(B) must have bought
(C) must be buying
(D) must buying
30) He _________ a few steps when it started raining.
(A) had hardly taken
(B) hardly took
(C) hardly taken
(D) taken hardly