UN Chinese Language Day ____ (celebrate) yearly on April 20. This year, Doreen Hynd was among those invitees, who are either experts on the Chinese culture ____ have a special skill related to it.

    Hynd astonished all those present while performing Tai Chi, ____ Chinese martial (武术的) art form, at an event held by the UN Tai Chi Club. The audience could hardly believe she was a 93-year-old grandma. It was definitely amazing that she could bend her body and raise her leg so ____ (easy) and keep herself still standing on one leg.

    Hynd owes (归功于) all this to her continuous practice of Tai Chi.

    Born in Australia in 1925, Hynd began Tai Chi training in her 50s and then moved to the US, ____ she later became an instructor herself.

    When ____ (ask) about the greatest benefit she gained from Tai Chi, Hynd said, “balance.” Hynd has been teaching people of all ages and different ____ (culture) backgrounds how to practice Tai Chi. They have benefited greatly from their association with the Chinese culture. They've developed a balanced state of mind and improved their health after ____（month）of practice. Tai Chi allows these people ____（understand）that, from the perspective（视角）of yin and yang, all things are closely connected with each other. This might be where the attraction of Tai Chi ____（lie）. Hynd enjoys sharing this great gift from China with her students.

周末小勇和同学骑车出游，在路上一辆汽车从小勇的后面飞快地向前驶过，若以汽车为参照物，则小勇是 ____（选填“前进”、“后退”或“静止”）的．小勇看到驶过的汽车后面卷起一团灰尘，这是因为：流体流速快的地方，压强 ____．当小勇看到前方有行人时，就按响了车铃，铃声是由铃碗的 ____产生的．

下列各句中，没有语病的一句是(　　)