Different places have different foods. South Korea is a rich country in A____ Seoul (首尔) is its capital city. It was called Hanyang a long time ____ Tian'an is an important city in ____(west) South Korea. You can____(taste)many kinds of fruits, such as sweet pears and grapes there. You can also eat some delicious food,____ (especial)cold noodles and pickles(泡菜). In China, there is a lot of____(interest)food. For example, in Beijing, it is ____(truly) that you can eat Beijing Duck. It's a Chinese t____ .It ____(take)a lot of work. If you want to know more about food, you can go o____to fin it.

已知$\cos 2\theta =\frac{\sqrt{2}}{3}$，则${\sin }^4\theta -{\cos }^4\theta$的值为（    ）

细菌、真菌培养的一般步骤是（ ）
①高温灭菌  ②接种  ③配制含有营养物质的培养基  ④恒温培养

下列句子中说法正确的是（    ）