问答题

Questions 12-16
Directions: Each of the following sentences or groups of sentences contains one, two, or three blanks. These blanks signify that a word or set of words has been left out. Below each sentence are columns of words or sets of words. For each blank, pick the oneword or set of words from the corresponding column that best completes the text. By ______ strict rules of hygiene in mater nity wards, Ignaz Semmelweis saved many women from dying of childbed fever, a fate that many expectant mothers feared.

Ａ. challenging

Ｂ. instituting

Ｃ. intimating

Ｄ. invalidating

Ｅ. sanitizing