题目

A gift is necessary when one is invited to visit friends in China. After greetings, the gift should be passed immediately to the host. Remember that usually Chinese people will not open the gift in front of the person who gives _________. To show the respect, it may be _________ to explain what the gift is. Bringing some nutrients and tonics (营养品、补品) to the elders in the family is a good idea. You can _________ prepare some small gifts for the spouse (配偶) or kids of the host. The host usually makes full _________ by carefully tidying up the house and __________ a lot of delicio下列反应的离子方程式正确的是A.把金属铁放入稀硫酸中2Fe+6H+=2Fe3++3H2↑B.碳酸钡与盐酸反应：BaCO3+2H+=Ba2++CO2↑+H2OC.往澄清石灰水中滴入少量的碳酸氢钠溶液：Ca2++OH-+HCO3-═CaCO3↓+H2OD.氢氧化钡溶液与稀H2SO4反应：Ba2++SO42-=BaSO4↓