Directions: Complete the following passage by using ONE word that fits the context.

Because neither she nor her husband smoked, Mrs. Trench was surprised to see cigarette ash on her doorstep as she entered the house. When she opened the living-room door, she was astonished to see a strange man fast      48     in an armchair! Taking care not to disturb him, Mrs. Trench left the house at once. She called a taxi and went      49     to the police station. When she got there, she lost no time to explain             _____50    had happened and added that the man      51     have got into the house      52    an open window. Mrs. Trench returned home       53      a police car together with two policemen. But it was too late: the man had disappeared. Hurrying upstairs, she went to her dressing-table. She smiled       54       relief when she saw the only thing that man had taken was an imitation diamond necklace that was almost      55      !

溶组织内阿米巴生活史的两个时期是指（）。

A.组织内滋养体和肠腔内滋养体

B.滋养体和包囊

C.环状体和配子体

D.速殖子和缓殖子

E.雌配子体和雄配子体