单项选择题A．six, more than 100B．two, more than 200C．two, more than 100D．six, more than 200

单项选择题A．wheat, soybeans, carrot and lettuceB．soybeans, tomatoes, carrot and wheatC．white potatoes, carrot, lettuce and soybeansD．wheat, soybeans; lettuce and white potatoes

单项选择题A．Scientists at the Kennedy Space Center are attempting to grow vegetables that could survive.B．In the special containers plants can develop rapidly in a short period of time.C．Scientists are also attempting to genetically design some of these plants to contain high levels of protein.D．Space agency scientists hope to test some version of the experimental gardens on the planned space station.

单项选择题A． shockB. horrorC. angerD. all of the above

单项选择题A．The membership fee is lower.B．They can help choose the products that will be sold.C．They may attend fewer meetings.D．They may go to the co-up more times per week.