安全水域标的特征是（）。
A.顶标为一红球
B.涂有红白横纹
C.顶标为一黑球
D.顶标为黑球
参考答案：A
根据句意及首字母提示，完成单词。
1. He often climbs m______ with his friends on Saturday morning.
2. —Which s_______ is the hottest in the year?
—It's summer.
3. The yellow l_______ fall from the trees in fall.
4. Fruit and crops are ripe. The farmers are busy h______ in fall.
5. Sometimes it rains q______ heavily.
When a new disease breaks out, experts must ________ what to do in the fastest way.[ ]
A. figure out
B. take out
C. point out
D. make out
