读一读，选出正确的汉语意思。

1. 我们在操场上跳房子。[ ]

A. We play on the playground.

B. We play hopscotch on the playground.

2. 我周三去学校。[ ]

A. I go to school on Thursday.

B. I go to school on Wednesday.

3. 该吃午饭了。[ ]

A. Time for lunch.

B. Time for bed.

4. 这是一间办公室。[ ]

A. This is an office.

B. This is a hall.

体内转运一碳单位的载体是（）

A.生物素

B.叶酸

C.维生素B₁

D.四氢叶酸

E.s-腺苷蛋氨酸