It is necessary ______ us to help our friends out when they meet difficulties．（ ）
A．toB．ofC．withD．for
With 5G network， driverless cars will run than before．（ ）
| A． |
safe |
B． |
safer |
| C． |
safely |
D． |
more safely |
Meimei is going to be an older sister．Her parents are planning to have their ________ child．（ ）
| A． |
one |
B． |
two |
C． |
first |
D． |
second |
If we walk in snowy weather， maybe we'll fall over．（ ）
| A． |
quickly |
B． |
friendly |
C． |
happily |
D． |
slowly |
I use your dictionary？
Sure， here you are．（ ）
| A． |
Must |
B． |
May |
C． |
Need |
D． |
Should |
Today many foreigners enjoy working or studying China．（ ）
| A． |
to |
B． |
by |
C． |
on |
D． |
in |