81. To my opinion, living in happiness for ten years ___________ a long time. A) has not been B) are not C) have not been D) will not be 82. His silence ________ that he agrees with us. A) mean B) means C) have meant D) meaning 83. Their news_______ to us once a year. A) come B) comes C) came D) has come 84. The police_________many enquires about the murder up till now. A) has made B) is making C) have made D) makes 85. All the equipment in this laboratory_________from Japan last year.. A) is imported B) will import C) imports D) was imported 86. His knowledge of butterflies, in fact,_______very wide. A) is B) are C) be D) to be 87. ______anybody at home? A) Are there B) Is there C) There is D) There are 88. One of the girls _________to visit that old man every Sunday. A) go B) goes C) went D) had gone 89. Mumps usually________a mild fever. A) cause B) have caused C) causes D) was caused 90. Everybody ______to do their best at present. A) are trying B) is trying C) try D) tries