1 . Most of us are familiar with carrots.     1     They are a cool-season crop that can tolerate low temperatures. 

    2     Firstly we should ensure that the soil used for deep-rooted types is free of stones. Mix the soil with organic matter, especially during the fall season before sowing. 

Then we should choose a variety of carrots after the soil is prepared.     3    The early ones are usually small, slender and are eaten while they are young; the main crop types are larger and are eaten fresh or stored. 

Early types should be sown in spring as soon as the soil is workable. They may also be sown under covers, though the covers should be removed after a few weeks.     4    Carrot seeds can be sown about 1/2 inch deep. Early carrots should be thinned to 3 inches apart; main crop carrots should be thinned to 1.5 inches. 

Weeds should be removed regularly once the carrots have germinated. Watering is needed every two to three weeks. Watch out for pests and diseases.     5     Protect against carrot rust flies by surrounding the patch of young carrots with a protective barrier 2 to 3 feet high. Use either fine netting or plastic as barriers. 

Early carrots can be harvested about seven to nine weeks after sowing and main crop carrots should be harvested after ten to eleven weeks.

More than 10,000 years ago, people in Mexico and Central America gathered and ate the fruit of wild avocado (牛油果) trees and    1    didn’t take long before they started to plant this high-fat, tasty food.

The name “avocado”    2    (be) from an Aztec word, ahuacatl, which refers to the shape of the fruit. The earliest evidence of human    3    (consume) of avocados is the seeds, or stones, found in Coxcatlan Cave in the Tehuacan Valley, Mexico,    4    have dated back to around 8,000 BCE. The high oil content of the avocado’s green flesh would have made the fruit a valuable addition    5    the prehistoric diet.

Domestication of the avocado soon followed, with the trees    6    (plant) in Mexico and Central America. By the time the explorer Christopher Columbus    7    (reach) South America in 1492, avocados were being consumed as far south as Peru. Today, Mexico is the world’s leading avocado producer, and the fruit is also    8    important crop in the US state of California, the Dominican Republic, and Indonesia.

With an amazing flavour, buttery flesh, and high nutrient content, the avocado has enjoyed a recent rise in popularity, and people continue to find innovative ways    9    (enjoy) it. It is perhaps most famous as the main ingredient of salad, but in Latin America avocados are still    10    (wide) used to garnish (搭配) chicken and potato soup.