本初子午线是指[ ]
A.最大的纬线圈
B.南北半球的分界线
C.东西经度的划分界线
D.东西半球的分界线
答案:C
用所给单词的适当形式填空。
1. We will ride (we) bikes to the store.
2. I need ten (gift) for my family.
3. Danny said he (want) a new car.
4. I (buy) a T-shirt last week.
5. Please (not) tell him about the party.
先天性心脏病形成的主要时期是()。
A.胚胎第2~4周
B.胚胎第2~8周
C.胚胎第4~10周
D.胚胎第6~10周
E.胚胎第8~12周