86. It is implied in the passage that ____.

1. patients prefer alternative medicines to conventional medicines
2. studies on alternative medicines are not necessary
3. researches on alternative medicines are making steady progress
4. alternative medicines lack scientific evidence

87. The author suggests that alternative medicines ____.

1. may not be as effective as their advocators claim
2. have been sponsored by the federal government
3. have been tightly controlled by the federal government
4. have attracted very few patients

88. Randomized controlled trials are the common methods for ____.

1. seizing the weaknesses of alternative medicine
2. assigning patients to treatment or control groups
3. eliminating bias from clinician and patient decisions
4. determining the effectiveness and safety of biomedical products

89. It can be safely concluded that ____.

1. small studies often have built-in conflict of interest
2. large-sized trials always lead to significant positive results
3. small-sized trials may lead to false results
4. small studies need to win grants for larger investigations

90. The study on the effects of extracts from the ginkgo biloba tree may produce significant results because ____.

1. it takes many years to conduct such large studies
2. it is a large study involving one clinical trial center
3. it studies the progression of Alzheimer's disease
4. it is a large study involving more than 3 000 patients

(Reference keys.)