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    In early spring, the changing temperature usually makes a number of Chinese people uncomfortable. Cold air, bringing rain or even snow, easily tears up(破坏) the warmth of the spring within a night(一夜之间).

    However, with the coming of Guyu-the Grain(谷物) Rain, the blue sky and gentle winds would finally stay. Falling usually on or around April 20 every year, Guyu is the sixth of the 24 solar terms(节气). It means the beginning of a lively summer and people get busy from now on.

    Sow(播种) grains

    This is an important period of the growth of grains. The ancient Chinese already knew that as Guyu comes, the weather will become warm enough for sowing. The farmers usually catch the chance to plant rice, corn and beans.

    Hope for safety and harvest

    For those living near the sea, they will hold some ceremonies(仪式) on Guyu, hoping for safety as well as harvest during the coming fishing season.

    Watch the peony

    It's also a great time to see the peony(牡丹), which is known as “the Queen of All Flowers” in Chinese culture. As a result, watching peonies becomes one of the most enjoyable activities for many. The flower is said to be the favourite of Empress(女皇) Wu Zetian of the Tang Dynasty, who was the only woman ruler in Chinese history.

    Pick tea leaves

    Tea leaves picked before Guyu are among the best tea leaves. People believe that the tea leaves picked on the day of Guyu can make eyes clear and drive away bad luck. So the habit of drinking tea at this time of year has become a tradition in some places of China.

在细胞工程—植物体细胞杂交中，需要将营养细胞的细胞壁除去，通常是采用纤维素酶和果胶酶的酶解破壁法处理。如将去掉了细胞壁的成熟植物细胞置于清水中，细胞将（　　）

It is ____. Let's go out.